Hemmi Catalogue Raisonne Main Page
Hemmi Slide Rule Catalogue Raisonné

This Catalogue Raisonne
describes every slide rule ever made by the Hemmi Slide Rule Company of Japan--or at least all those I have been able to identify. It is the most comprehensive catalogue of Hemmi slide rules ever published. There are two parts: (1) This page lists Hemmi slide rules for which a model number is known. (2) The second page contains descriptions of Hemmi-made slide rules for which I have not been able to determine a model number. They are usually rules with names rather than numbers or military rules or rules sold under another company's (Post, Foxboro, SKF, etc.) name.

Construction material is celluloid on bamboo except for model number which begin with "P" (e.g., "P23") which are all plastic and for a few rules whose substance is explicitly mentioned in the text.

This is an updated version of the Comprehensive Hemmi Catalog which was published in the Spring 2003 issue of the Journal of the Oughtred Society. It is based upon about 500 documents, photographs and specimen slide rules, many of which were supplied by my friends in Japan: William Lise, Atsushi Tomozawa, Yukio Kubota and Hitoshi Nori; I cannot begin to express my gratitude to them. Many errors exist in spite of their efforts and this catalog remains a work in progress. I will be grateful to anyone who can supply missing information or pictures or point out errors. I am indebted to Tom Dilatush for prolonged discussions of how this information should be organized and displayed.

You may also be interested in A Hemmi Chronology. It lists the important dates and shows how markings on Hemmi rules changed from time to time.

Paul Ross, Feb 2022
Model
Dates

Front Scales
Rear and Other Calculating Scales
Body
Comment
Also Sold As
Models1-18: Obsolete Model Numbers Abandoned About 1930.
1
1/1
1913-29
Pic
A [B, C] D
[S, L, T]
//Closed||
250 x 28 x 9.5 mm
Mannheim. ("Normal") Listed as obsolete starting in 1936 but price listed in Hemmi catalogs through 1937 and available from Frederick Post (as model 1449) through 1940.
Tamaya 1941 (1916-27);
H-O 1768 (-1914-);
Post 1449 (1930-WWII)

Pic
Artillery variant with minutes and mils conversion scales on bottom edge and trigonometric formulas for gunnery on back of rule. Dates probably later than model 1.

Pic
A [B, Stadia, C] D
Stadia variant. Stadia scale (SinCos and Cos²) added to front of slide. Dates probably later than model 1.
2
1913-29
Pic
Same as model 1 but with decimal-indicating cursor. //Closed||
250 x 28 x 9.5 mm
Discontinued ca1929.
Tamaya 1937 (1913-27);
H-O 1767 (-1914-28-)
3
1919-29
Pic
LL2, A [B, C] D, LL3
[S, L, T]
Gutter: E, F
//Closed||
250 mm
x 1½ in x 10 mm
Electro. (Copy of Faber 378) LL scales keyed to offset W gauge mark. E,F scales separated in gutter. No over-range. HP gauge mark (probably only 746). Single hairline. At least three different cursors. Tamaya 1905 (1919-27); H-O 1770 (1928), Hemmi 80 (1930+).
4
1919-29
Pic
Same as 3 but with decimal-indicating cursor.

Tamaya 1904 (1916-27), Hemmi 81 (1930+
5
1919-29
Pic
A [B, C] D
[S, L, T]
//Closed||
500 mm x 1¼ x 13/32 in
Listed as obsolete by Hemmi in 1936 but price listed through 1937. In Post catalog (model 1450) until WWII and in H-O catalog (model 1772) though1948.
Tamaya 1899 (1916-27);
H-O 1772 (1928);
Post 1450 (1936-WWII).
6
1919-29
Pic
A [B, C] D
[S, L, T]
//Closed||
125 x 24 x 9 mm
Pocket Mannheim. Replaced by model 48 ca1930. H-O 1763 (-1914-35);
Tamaya 1942 (1916-27).
7
1926-29
Pic
Same as 6 but with decimal-indicating cursor

Tamaya 1949 (1927)
8
1913-29
Pic
A [B, C] D
[S, L, T]
/Closed||
125 x 24 x 9 mm
Extra Fine Mannheim w Magnifier.
Tamaya 1943 (1916-27);
H-O 1764 (-1914-48-)
9
1919-29
Pic
Same as 8 but with magnifiying decimal-indicating cursor
Discontinued ca1929.
Tamaya 1900 (1916-27)
10
1926-29
Pic
A [B, C] D
[S, L, T]
//Closed||
250 mm
Ten-inch extra fine with "extended lens" magnifier. Discontinued ca1929.
Tamaya 2148 (1927)
11
1926-29
Pic
Same as10 but with decimal-indicating "extended-lens" cursor.
Discontinued ca1930.
Tamaya 2180 (1927)
12

NA
DF [CF, CI, C] D
(Folded at ?)
Blank
?
150 mm
Simplified Slide Rule. Plastic.
Single uncorroborated reference.

12
1926-29
Pic
Same as model 3 but with "extended-lens" magnifying cursor.
Discontinued ca1929.
Tamaya 2782 (1927)
13
1926-29
Pic
Same as 4 but with decimal-indicating "extended-lens" cursor.
Discontinued ca1929.
Tamaya 2783 (1927)
14
1926-29
Pic
A [B, C] D
[S, L, T]
||Closed||
100 mm
x 11/16 x 7/32 in
Vest Pocket Mannheim with square edges.
Tamaya 2784 (1927);
Hemmi 35 (1930+)
15
1926-29
Pic
Same as 14 but with decimal-indicating cursor.
Discontinued ca1929.
Tamaya 2785 (1927)
16
1926-29
Pic
Same as 14 but with magnifying cursor.
Discontinued ca1929.
Tamaya 2786.
Hemmi 35ML (1930+)
17
1926-29
Pic
Same as 14 but with magnifying decimal-indicating cursor.
Discontinued ca1929.
Tamaya 2787
18
1826-29

Pocket kit including pen, pad and model 15 slide rule. Discontinued ca1929.
Tamaya 2788
19
1927
Pic
A [B, C] D
[S, L, T] ?
250 mm
Student version of model 1. Model number may have been changed to 40 before any were actually sold.
Model Numbers 20-24 were assigned to Classroom Demo Slide Rules before WWII; Student Rules after WWII.
20 1932-42
NA
A [B, CI, C] D, K
[S, L, T]
Demo
2000 mm
Demonstration Mannheim (Model 50)
Tamaya 4451 (1932)
21
1932-42
NA
K, A [B, CI, C] D, L with over-range
[S, S&T, T]
Demo
2000 mm
Demonstration Rietz (Model 64).
Tamaya 4452 (1932)
22
1951-59
Pic
[CI, C] D, A
No back
Special
200 x 23
x 9 mm
Cheap student rule distributed in Asia only. Slide held to single stator. Some (1955 only?) sandalwood, not bamboo. Celluloid cursor.

P23
1957-69
Pic
A [B, CI, C] D
A [B, CI, C] D
Open
180 mm
x 1 x 1/8
in
Student Mannheim w CI scale.
Hemmi's first plastic-based rule.

24
1927
Pic
A [B, C] D
Blank
//Closed||
125 x 26 x 3 mm
Ultra-thin all plastic with celluloid cursor. 13 cm scale on top edge; bottom blank. Identical to model 34 except imprinted with advertising. Rare. Appears in no known catalog.
P24
1963-69
Pic
DF [CF, CI, C] D, A
Folded at √10.

Blank
Open
180 mm x 1 x 1/8 in
Student.

Models 30-39: Miscellaneous Four- and Five-inch Closed Body Slide Rules
30
1930-43
Pic
A [B, C] D
[S, L, T]
//Closed||
100 mm x 11/16 x 7/32 in
Vest Pocket Mannheim. Model number never appears on rule. Some w "SUN" cut through or "SKF" embossed into backing plate. 1000¥ ($2.78) in 1969.
Tamaya 4453 (1927);
Post 1447 (1931-33);
Post 1440 (1934-WWII)
31
1930-42
Pic
Same as 30 but with decimal-indicating cursor.
No CI scale
Tamaya 4454
32
1930-42
Pic
Same as 30 but with magnifying cursor. Tamaya 4455; Post 1447M (1931-33); 1441 (1934-WWII);
Boston Blue Print 1441; US Blue 1888.
33
1930-42
Pic
Same as 30 but with decimal-indicating magnifying cursor
No CI scale
Tamaya 4456
30R
MIOJ-1950
Pic
A [B, CI, C] D [S, L, T]
(S keyed to A/B except WWII-1955 keyed to C/D)
//Closed||
100 mm x 11/16 x 7/32 in
Vest Pocket Mannheim w CI scale. No model number on rule but case and box marked "30R."
Fuji 41.
Post 1440.  

30
1951-EOB
Pic
Same rule with "R" dropped from model number on case and box. All-plastic cursor after ca 1970.
32R
MIOJ-1950
Pic
Same as 30R but with magnifying cursor
Post 1441(WWII-1971);   T-P 44DA-410 (1972+);
H-O 1760 (-1952-64);       Geo 341-3405 (1964+)
US Blue 1888 (MIOJ)
32
1951-EOB
Pic
Same as 30 but with magnifying cursor.
P33S
1971
Pic
A [B, CI, C] D, K
[S, L, T]
(S keyed to C/D)

Closed
125 x 28 x 5 mm
Pocket Improved Mannheim. All-plastic version of model 34RK.

P33/SS
1970
Pic
A [B, CI, C] D, K
[S, L, T]
(S keyed to C/D)

Closed
125 x 27 x 4.5 mm
Pocket Improved Mannheim. Unique size.
Geotec 341-3610
34
1932
Pic
A [B, C] D
Blank
//Closed||
125 x 26
x 3 mm
Ultra-thin all plastic with celluloid cursor. 13 cm scale on top edge; bottom blank
Hemmi 24;
Tamaya 4457
34P

1932-42
NA
A [B, C] D Blank //Closed||
125 mm x 15/16 x 5/32 in
Thin Pocket Mannheim with blank back.
Post 1443 (1931-WWII)

MIOJ
Pic
//Closed||
125 x 26 x 5 mm

34π

1932-42
Pic
CF [DF, CI, C] D
Folded at π
[S, L, T]
(S keyed to C/D)
//Closed||
125 mm x 15/16 x 5/32 in
Thin Pocket Mannheim with folded scale.
Post 1444 (c1935-WWII);
H-O 1762 (-1935-WWII)
MIOJ
NA
//Closed||
125 x 26
x 5 mm

34R

1935-40
Pic
A [B, CI, C] D [S, L, T]
(S keyed to A/B except WWII-1955 keyed to C/D)
//Closed||
125 mm x 15/16 x 1/8 in
Thin Pocket Mannheim w CI Scale.
Post 1444 (c1935-WWII);
H-O 1762 (-1935-WWII)
1955-68 NA
//Closed||
125 x 26
x 5 mm

34RK
1936-EOB
Pic
A [B, CI, C] D, K
[S, L, T]
(S keyed to A/B except WWII-1955 keyed to C/D)

//Closed||
125 x 26
x 5 mm
Post 1444K (1937-70),1444(1971); T-P 44DA-440 (1972+);
US Blue 1887 (1930s); H-O 1762 (WWII-64); Geo 341-3425 (1964+).
34T
1936-42
Pic
A [B, C] D
[S, L, T]
//Closed||
125 mm x 15/16 x 1/8
in
Thin Pocket Mannheim. "SUN" or ASEA embossed into backing plate.


35
1935-48
Pic
A [B, C] D
[S, L, T]
||Closed|| 100 mm x 11/16 x 3/16 in
Vest Pocket Mannheim with 4-inch and 10-cm measuring scales on square edges Hemmi 14;
Post 1437 (c1935-WWII);
H-O 1761 (-1935-48-)
35ML
1930s
Pic
Same as 35 but with magnifying cursor Hemmi 16
P35
B35
1959-61
Pic
K, DF [CF, CI, C] D, A
Folded at √10.
Blank
Open
115 mm x 1 x 1/8 in
Marked "B35" (factory error for "P35"?); thin bamboo core covered with PVC (not celluloid); scales printed (not engraved).  All known specimens also marked H-O 1759.
P35S
1971
Pic
K, DF [CF, CI, C] D, A
Folded at √10.
[LL1, LL2, LL3]
Closed
125 x 28 x 4.6 mm


36
1936-WWII
Pic
A [B, CI, C] D
[S, L, T]
Closed
125 mm x ¾ x 7/32 in
Narrow Pocket Mannheim w CI scale. Measuring scales on BACK of rule.
Post 1438 (c1935-WWII)
P36
P36S
1966-70
Pic
D [Conversion gauge marks, A] D
Instructions [Conversion gauge marks, B] Instructions
Open
115 mm x 1 x 1/8 in
Rule is labeled "P36;" box and instructions "P36S." Set arrow on slide opposite value on top D scale; converted value appears on bottom D scale opposite corresponding arrow. Reverse slide for more conversions. Markings and instructions in Japanese. 450¥ ($1.25) in 1969.
P37
1966-70
Pic
(1), (2), D [C, CI, B] MD1, MD2
[B, PR1, PR2, PR3]
Closed
125 x 28 x 4.6 mm
SALES. Labeled in Japanese. MD1 is months and days from 1/1 to 6/30, MD2 from 7/1 to 12/31. PR1-2-3 = three short profit ratio scales. Reverse slide to read B, PR scales.. {Two hairlines: D: 1.2}. 700¥ ($1.94) 1969.
P39

NA
K, A, DF [CF, CIF, CI, C] D, DI, L
Folded at ?

[B, TI, SI, C]
Closed
125 mm
Single uncorroborated reference.

Models 40-49: Basic Mannheim Rules (A [B, C] D) before WWI and "Improved" Mannheim (A [B, CI, C] D, K) after WWII.
40
1932-49
Pic
A [B, C] D
[S, L, T]
Closed
250 x 28 x 8 mm
Tamaya 4458 (1927), Post 1446 (1931-49); H-O 1768 (-1935-48-); Boston Blue Print 1446; US Blue 1876 (1930s); Lietz 2974N (1930s).
41
1932-42
Pic
A [B, C] D
[S, L, T]
Closed
125 mm
Pocket Mannheim. No measuring scales Tamaya 4459 (1932)
42
1932
Pic
A [B, C] D
[S, L, T]
Closed
250 x 28 x 8 mm
Model 40 w measuring scales on BACK. Tamaya 4460 (1932)
43
1932
NA
Same as 42 but with decimal-indicating cursor.
Tamaya 4461 (1932)
44
1932
Pic
A [B, C] D
[S, L, T]
Closed
125 mm x 15/16 x ¼ in
No slant; cm & inch scales on back of rule. Tamaya 4462 (1932)
45
1932 NA
Same as 44 but with decimal-indicating cursor. Tamaya 4463 (1932)
45
1949-68
Pic
DF [CF, CI, C] D, A
Folded at √10.
[TI, L, SI]
Closed
200 x 28 x 8 mm
Student. Quite different from 1932 model 45.

46
1936-42
Pic
A [B, C] D
Blank
Special. 125 mm x 1 in
"Cardboard covered in transparent celluloid with leather sheath."

47
1936-42
Pic
A [B, C] D
[S, L, T]
//Closed||
250 x 28 x 8 mm
Thin successor to model 1/1.
Post 1449T (1937-WWII)
48
1932-42
Pic
A [B, C] D
[S, L, T]
//Closed||
125 mm x 15/16 x ¼ in

Pocket Mannheim. Thin successor to model 6.

40F
1968-69
Pic
K, DF [CF, CI, C] D, A
Folded at √10

[TI, L, SI]
Closed
250 x 28 x 8 mm

Fuji 85.
40RK

1949-69
Pic
A [B, CI, C] D, K
[S, L, T]
(S keyed to A/B except Staedtler 944-55 keyed to C/D)
Closed
250 x 28 x 8 mm
Improved Mannheim. ("Slide Rule with CI and K Scale" in early literature)

Post 1447 (c1949-1971);
H-O 1768C (-1952-64);
Geo 341-3526 (1964-71);
US Blue 1877 (1940s?).
1973
Pic
Same as preceding but wider with thick plastic back. Closed
250 mm x 1¼ x 9/32 in
T-P 44BA-470 (1972+);
H-O 341-3526 (1972+)
40-50

Pic
Overhead projection rule for Hemmi model 40RK. Projection 305 x 182 x 12 mm


P
40RK
1967-69
Pic
A [B, CI, C] D, K
[S, L, T]
Open
250 x 28 x 8 mm
All-Plastic Improved Mannheim. Hard plastic case.
Post 1447P (c1967);
Geo 341-3530 (c1967)
43A
1961-71
Pic
A [B, CI, C] D, K
[T, L, S]
(S keyed to C/D)
Closed
200 x 28 x 8 mm
Student Improved Mannheim.

P43D
1973-EOB
Pic
A [B, CI, C] D, K
[T, L, S]
(S keyed to C/D)
Closed
200 x 28 x 6.4 mm
Like 43S except no indices on back of rule; slide must be reversed.

P43S
1969
Pic
A [B, CI, C] D, K
[T, L, S]
(S keyed to C/D)
Closed
200 x 28 x 6.4 mm
Plastic version of 43A. Indices for reading trig scales on back of rule.

45K
1962-EOB
Pic
K, DF [CF, CI, C] D, A
Folded at √10.
[TI, L, SI]
Closed
200 x 28 x 8 mm
Post 1445 (c1966-71); T-P 44BA-450 (1972+);
Geo 341-3500 (1967+).
All have scales folded at π.
P45K
1965-69
Pic
K, DF [CF, CI, C] D, A
Folded at √10.
[TI, L, SI]
Open
200 x 28
x 5 mm
Open body all-plastic version of 45K
Post 1445P (-1965-)
Scales folded at π.

P45D
1973-EOB
Pic
K, DF [CF, CI, C] D, A
Folded at √10.
[T, L, S]
Closed
200 x 28 x 6.4 mm
"Junior High School Students." Like P45S except trig scales not inverted and no indices on back of rule; slide must be reversed.
P45S
1969-73
Pic
K, DF [CF, CI, C] D, A
Folded at √10.
[TI, L, SI]
Closed
200 x 28 x 6.4 mm
Closed body all-plastic version of 45K. Simpler construction than P45K.

Models 50-59: "Improved" Mannheim Slide Rules (A [B, CI, C] D, K and [S, L, T]) and Variants.
50, 50/1,
50/3
1932-51
Pic
A [B, CI, C] D, K
[S, L, T]
(S keyed to A/B except WWII-1955 keyed to C/D)
//Closed||
250 x 28 x 10.5 mm
Improved Mannheim. Formerly model 102.
Hemmi 102; Tamaya 4464 (1932); Post 1452 (c1935-51); H-O 1771 (-1928-48-);
US Blue 1880 (1930s).
50F, 50/1F
1936-MIOJ
Pic
A [B, CI, C] D, K
[S, L, T]
//Closed||
250 x 28 x 8 mm
Thin version of 50, 50/1 but accepts standard cursor.
Post 1452T (1936-WWII).
50π/1
1936-42
Pic
A, DF [CF, CI, C] D, L
Folded at π.
[S, S&T, T]
//Closed||
250 x 28 x 10.5 mm


Post 1455 (c1935-WWII).
50W 1951-EOB
(For Post)
Pic
A [B, CI, C] D, K
[S, L, T]
(S keyed to A/B except WWII-1955 keyed to C/D)
//Closed||
250 x 34 x 11 mm
Wide Improved Mannheim.
Post 1452W ('51-70), 1452 ('71); T-P 44BA-520 ('72+);
H-O 1771 ('51-64);
Geo 341-3215 ('64+).
P50
1965?-68?
NA
A [B, CI, C] D, K
Blank
Open?
250 mm x 1½ in
Improved Mannheim.

50-20

1935-48
Pic
A [B, CI, C] D, K
[S, L, T]
//Closed||
500 x 34 x 11 mm
Long Improved Mannheim. Made for Post & H-O only; not sold as Hemmi brand.
Post 1454 (-1936-WWII);
H-O 1772 (-1935-58-)
H-O 341-3235 (-1969-).
WWII-1969
Pic
//Closed||
500 x 40 x 12 mm
Wide Long Improved Mannheim. Hemmi & Post brands.
{Three Hairlines: D: C, C}.
51/1, 51/3
1932-42
Pic
Same as 50/1, 50/3 but with decimal-indicating cursor.
Formerly model 103. Tamaya 4466, 4467 (1932).
52
1932-42
Pic
A [B, CI, C] D
[S, L, T]
//Closed||
125 mm x 15/16 x 11/32 in
Thicker than 34R.

Tamaya 4468;
Post 1448 (1936-37).
53
1932-42
Pic
Same as 52 but with decimal-indicating cursor.
Tamaya 4469 (1932).
54
1936-42
Pic
A [B, CI, C] D, K
with over-range
[S, L, T]
//Closed||
150 x 26 x 6 mm
"Extra Fine Improved Mannheim" with magnifying cursor.
Post 1453 (c1935-WWII).
55
1936-42
NA
Same as 54 but without magnifying cursor.


Models 60-79: Rietz Slide Rules ( K, A [B, C] D, L and [S, S&T, T] )
60/1, 60/3

1932-3x
Pic
K, A [B, C] D, L
[S, S&T, T]
//Closed||
250 mm x 1¼ x 13/32 in
Rietz. Single line model 60/1 discontinued ca 1930. Tamaya 4470, 4471 (1932)

193x-42
Pic
K, A [B, C] D, L
with over-range
61/3
1932-42
NA
Same as 60/3 but with decimal-indicating cursor.


62/3
1932
NA
K, A [B, C] D, L
[S, S&T, T]
//Closed||
150 mm
Extra Fine Rietz. Tamaya 4472, 4473 (1932)

63/3
1932
NA
Same as 62/3 but with decimal-indicating cursor.
64, 64/1, 64/3
1932-68
Pic
K, A [B, CI, C] D, L
with over-range
[S, S&T, T]
//Closed||
250 x 34
x 11 mm
"System Rietz." {64/3 hairlines: D: C, C} Some w 13-0-13 cm on bottom. Probably without over-range before 1935.
Tamaya 4474 (1932)
64T
1965-71
Pic
K, A [B, BI, CI, C] D, DI, L
with over-range
[T2, T1, ST, S]
//Closed||
250 x 34
x 11 mm
"Super Rietz." {3 hairlines: D: C, C}.
65
1932-42
Pic
Same as 64/3 but with decimal-indicating cursor. //Closed||
250 x 34
x 11 mm

Tamaya 4475 (1932)
66
1932-68
Pic
K, A [B, CI, C] D, L
with over-range
[S, S&T, T]
//Closed||
150 x 26
x 9 mm
Extra Fine Improved Rietz.
{3-line cursor: D: C, C}
Some 8-0-8 cm on bottom.
Tamaya 4476 (1932)
66F
1936-42
Pic
Same as 66 but thin.


67
1932-42
NA
Same as 66 but with 3-line magnifying cursor.

Tamaya 4477 (1932)
68
1932-42
NA
Same as 66 but with 3-line decimal-indicating cursor.

Tamaya 4478 (1932)
69
1932-42
NA
Same as 66 but with 3-line decimal-indicating magnifying cursor.

Tamaya 4479 (1932)
70 1932-43
Pic
K, A [B, CI, C] D, L
some with over-range

[S, S&T, T] //Closed||
500 x 34
x 12 mm
Long Improved Rietz.
{3 hairlines: D: C, C}.

Tamaya 4480 (1932)
1951-70
Pic
//Closed||
500 x 40
x 12 mm
72
1966-71
Pic
K, DF [CF, CIF, CI, C] D, A
with over-range
Folded at √10.

[TI2, TI1, L, SI]
//Closed||
500 x 40
x _ mm
"Precision Slide Rule for Practical Engineers." Single hairline.

74
1937-EOB
Pic
K. A [B. CI. C] D, L
with over-range
[S, S&T, T]
//Closed||
125 x 26
x 5 mm
Pocket Improved Rietz.
{3 hairlines: D: C, C}.

Models 80-89: "Electro" Slide Rules
80
80/1
80/3
1930-32
Pic
LL2, A [B, CI, C] D, LL3
No over-range

No over-range
[S, L, T]
E, F widely separated in gutter.

//Closed||
250 mm x 1 ¼ in x 10 mm
Electro. LL scales keyed to offset "W" gauge mark. No over-range. Same as model 3 with CI scale added. Hemmi 3;
Tamaya 4481, 4482 (1932);
H-O 1770 (-1928-c50);
Post 1456 (c1934-WWII)
1932-33
Pic
//Closed||
250 x 34 x 11 mm
Same as preceding but on slightly wider body.
1934-36
Pic
[S, L, T]
E, F close together in gutter

Same as preceding but no "W" gauge mark. E, F close together in gutter.
1936-52
Pic
LL2, A [B, CI, C] D, LL3
with over-range
Same as preceding but with over-range extensions.
81/1, 81/3
1932-42
Pic
Same as 80/1, 80/3 but with decimal-indicating cursor. Details vary depending upon date of manufacture.  See model 80.
Hemmi 4;
Tamaya 4482, 4484 (1932)
82 1932-37
NA
Same as 80/1 except short. //Closed||
125 x _
x 9 mm




Tamaya 4485 (1932)
83
1932-37
NA
Same as 82 but with decimal-indicating cursor.
Tamaya 4486 (1932)
84
1932
NA
Same as 82 but with magnifying cursor.
Tamaya 4487 (1932)
85
1932
Pic
Same as 82 but with magnifying decimal-indicating cursor. Tamaya 4488 (1932)
85
MIOJ
Pic
db, Neper, A [B, CI, C] D
[TI2, TI1, L, SI1]
//Closed||
250 x 34 x 11 mm
Not electro, therefore model number 85 is inappropriate.  {3 hairlines: A: C2, 1.307} (Why 1.307?)
Rare.
80K
1953-70
Pic
E, F, A [B, CI, C] D, LL2, LL3
with over-range
[S, L, T]
Bottom Edge: K
//Closed||
250 x 34 x 11 mm
Electro. K scale on bottom edge; no scales in gutter. No hp mark but different cursors avail for British/US and French/Metric HP. {3-line cursor: A: hp, C2}.
86/3
1936-42
NA
LL2, A [B, CI, C] D, LL3
with over-range
[S, L, T]
Gutter: E, F
//Closed||
150 x 26 x 8 mm
"Extra fine Electro." Hp gauge mark. No W mark. E,F scales close together in gutter. {Three hairlines: A: hp, C2}.

87/3
1936-42
NA
Same as 86/3 but with magnifying cursor.


86/3K
1950
Pic
LL2, A [B, CI, C] D, LL3
with over-range
[S, L, T]
Gutter: E, F
Bottom Edge: K
//Closed||
150 x 26 x 8 mm
Same as model 86/3 except K scale added to bottom edge.

86
1951
Identical to and contemporaneous with model 86/3K.

86K
1954-70
Pic
E, F, A [B, CI, C] D, LL2, LL3
with over-range
[S, L, T]
Bottom Edge: K
//Closed||
150 x 26 x 8 mm
"Extra Fine Electro." No scales in gutter, no hp mark. {Three hairlines: A: hp, C2}.

Models 90-99: Stadia Slide Rules
90
1932-42
Pic
L, D [M1, M2, C] D, A with over-range [S, S&T, T]
Bottom Edge: K, IA
//Closed||
250 x 34 x _ mm
Stadia. {3 hairlines: D: C, C}. Two calculating scales on bottom edge. IA scale read from offset pointer keyed to rightmost hairline.
90A
1940
NA
Same as 90
90B
1939?
Pic
Same as 90 but uses "centesimal degrees."
(100 centesimal degrees = right angle)
First of a proposed series (models 90B, 91B, 2690B) of centesimal-degree stadia rules. Models 91B and 2690B were never manufactured.
91
1932-42
Pic
Same as 90 but with decimal-indicating cursor

Tamaya 4490 (1932)
91A
1939?
NA
Same as 91. "91A" used to distinguish this rule from proposed centesimal degree model 91B.
92
1932-42
Pic
L, D [M1, M2, C] D, A
[S, S&T, T]
Bottom Edge: K, IA
//Closed||
150 x 26 x 9.6 mm
"Extra Fine Stadia." Two calculating scales on bottom edge. {3 hairlines: D: C, C}. Tamaya 4491 (1932)
93
1932-42
Pic
Same as 92 but with magnifying cursor.
Tamaya 4491 (1932)
94
1932-42
NA
Same as 92 but with decimal-indicating cursor.
Tamaya 4491 (1932)
95
1932-42
NA
Same as 92 but with decimal-indicating magnifying cursor
Tamaya 4491 (1932)
96
1936-43
Pic
L, D [M1, M2, C] D, A
with over-range.
[S, S&T, T]
Bottom Edge: K, IA
//Closed||
500 x 34 x 11 mm
Long version of model 90. {3 hairlines: D: C, C}. Two calculating scales on bottom edge. IA scale read from offset pointer keyed to center hairline.
Model Numbers 100-107 were assigned to new rules developed in 1926-27; all were replaced by modern numbering system about 1930.
100
1926-27
Pic
A [B, CI, C] D
[S, L, T]
//Closed||
250 mm
Short lived.
Tamaya 2790 (1927)
101
1926-27
Pic
Same as 100 but with decimal indicating cursor.
Tamaya 2791 (1927)
102
1926-28
Pic
A [B, CI, C] D, K
[S, L, T]
//Closed||
250 x 28 mm
Improved Mannheim. Model number changed to 50/1 ca 1928.
Tamaya 2792 (1927),
H-O-1771
103
1926-28
Pic
Same as 102 but with decimal-indicating cursor.
Model number changed to 51/1 ca 1928.
Tamaya 2793, (1927)
104
1927
Pic
LL2, A [B, CI, C] D, LL3
No over-range
[S, L, T]
Gutter: E, F
//Closed||
125 mm
"Pocket Electro." LL scales keyed to offset W gauge mark. E,F scales separated in gutter. No over-range. Hp gauge mark. Hemmi 82;
Tamaya 2994 (1927)
105
1927
Pic
Same as 104 but with decimal-indicating cursor. Hemmi 83, Tamaya 2995
106
1927
NA
Same as 104 but with magnifying cursor.
Hemmi 84, Tamaya 2996
107
1927
NA
Same as 104 but with magnifying decimal-indicating cursor.
Hemmi 85, Tamaya 2997
Models 100-109: Large Classroom Demonstration Slide Rules
100
1951-68
Pic
DF [CF, CI, C] D, A
Folded at √10.
[TI, L, SI]
Demo
1000 mm
Demonstration version of model 45.

100K
1969-71
Pic
K, DF [CF,CI, C] D, A
Folded at √10
[TI, L, SI]
Demo
1000 mm
Demonstration version of model 45K

101
1951-68
NA
ℓ, A [B, CI, C] D
[S, K, T]
(S keyed to C/D)
Demo
1000 mm
Demonstration version of model 2640.

101A
1967-EOB Pic
A [B, CI, C] D, K
[S, L, T]
(S keyed to C/D)
Demo
1000 mm
Demonstration version of models 40RK & 43A.

102
1954-68
Pic
CI, C, [D, A]
Blank
Demo
1000 mm
Demonstration version of model 22.

103
1959-EOB
NA
K, DF [CF, CIF, CI, C] D, A
Folded at √10.
[TI1, TI2, L, SI]
Demo
1500 mm
Demonstration version of model 2664S.

104
1959-69
NA


Demo
1000 mm
Demonstration.

107
1969-EOB
NA
LL3, LL2, DF [CF, CIF, CI, C] D, L, LL1     Folded at √10.
K, A [B, TI1, TI2, SI] D, DI
Demo
1000 mm
Demonstration version of model P253.

108
1971?
NA
LL/1, LL/2, LL/3, DF [CF, CIF, CI, C] D, LL3, LL2, LL1
Folded at √10
K, A [B, TI, SI, C] D, DI, L
Demo
1000 mm
Demonstration version of model 254W.

Models 110-129: Specialty Slide Rules
110
1937-MIOJ
Pic
LL2, A [B, CI, C] D, LL3
with over-range
[S, S&T, T]
Bottom Edge: K
//Closed||
250 x 34 x 11 mm
Mechanical /Electrical slide rule. K scale on bottom edge. {Three hairlines: D: C, C}.

120
1939?
Pic
L, K, A [B, CI, S1, T1, C] D, SΘ
with over-range
[LL3, LL3, LL2, LL2, LL1, LL1]
Bottom Edge: GΘ
(2 scales)

//Closed||
250 x 34 x 11 mm
"MIGHT." Listed without description by Katsunori Kadokura (Chronology of Japanese Hemmi Slide Rules, Journal of the Oughtred Soc, Vol 1, No 2, August 1992). Pictured specimen identified as Model 120 by Yukio Kubota, March 2014.
DP121
1968-69
Pic
LL3, LL2, DF [CF, CIF, CI, C] D, L, LL1
K, A [B, TI2, TI1, SI] D, DI
Projection 305 x 182 x 12 mm
Overhead projection rule for model P253. Sold with five masks for obscuring irrelevant scales.
¥10,000 in catalog dated 6911
DP122
1968-69
Pic
K, A, DF [CF, CIF, CI] D, DI, L
K, A, DF [B, TI2, TI1, SI, C] D, DI, L
Projection 305 x 182 x 12 mm
Overhead projection rule for models 2662 and 2664S. Sold with five masks for obscuring irrelevant scales.

Models 130-139: Darmstadt Slide Rules (L, K, A [B, CI, C] D, Cos, Sin, Tg and [LL1, LL2, LL3]) and Variants
130
1950-69
Pic
L, K, A [B, CI, C] D, Cos
with over-range
[LL1, LL2, LL3]
Bottom Edge: SIN, tg
//Closed||
250 x 34 x 11 mm
Darmstadt. S and T scales on bottom edge of rule.
{3 hairlines: D: hp-C, C}.

130W
1970-72
Pic
T, K, A [B, BI, CI, C] D, P, S
with over-range
[L, LL0, LL1, LL2, LL3]
//Closed||
250 mm x 1½ x 7/16 in
Advanced Darmstadt. Unique width.
{3 hairlines: A: C2, hp-C2}.

135
1959-71
Pic
T, K, A [B, CI, C] D, P, S
with over-range
[L, LL1, LL2, LL3]
//Closed||
125 x 26 x 5 mm
Pocket Darmstadt.
{3 hairlines: D: hp-C, C}.

P135k
2005
Pic
T, K, A [B, CI, C] D, P, S
with over-range
[L, LL1, LL2, LL3]
Closed
200 x 32 x 4.3mm
Darmstadt. Only 250 made. Manufactured by HEMMI in 2005 to specifications of ISRG and Japanese collectors and sold by subscription.
136
1951-68
Pic
L, K, A [B, CI, C] D Cos
with over-range
LL1, LL2, LL3]
Bottom Edge: SIN, tg
//Closed||
150 x 26 x 8 mm
Extra Fine Darmstadt. D scale is labeled "SIN" other scales not labeled.

Models 140-149: Pocket Duplex Slide Rules
140
MIOJ
Pic
DF [CF, CI, C] D, L
Folded at √10.
K, A [B, TI, SI, C] D, DI
Duplex
150 mm x 1 3/16 x ¼ in
Hemmi's first "pocket" duplex. Body is short version of old narrow model 150.

141
P141
1960-EOB
Pic
LL/1, LL/2, LL/3, DF [CF, CIF, CI, C] D, LL3, LL2, LL1
Folded at π
T, S, U, P [Q, c, V, R] A q, n, L
Duplex
125 x 34 x 4 mm
Air conditioning duct design. Bamboo (141) and all-plastic (P141) versions. Same blank as 149. All-plastic version marked "'Carrier' Ductuler" (Toyo Carrier Corp). Some bamboo specimens carry no brand name, some marked "Carrier 50210," others marked "Shin Nippon Kucho." (SNK was spun off from Toyo Carrier in 1969.)
143
1968-69
Pic
P1, P2, DF [CF, CIF, CI, C] D, LL (2 scales) 
Folded at 360.
A, N [M, £, S/d, C] D, G Duplex
125 x 34 x 4 mm
"Commerce." N, M have 365 division for dates. £, S/d = pound/ shilling/ pence. G is a set of conversion gauge marks.
Pocket version of model P263.
149
1959-1962
Pic
LL/1. LL/2, LL/3, DF [CF, CIF, CI, C] D, LL3, LL2, LL1
Folded at π.
L, K, A [B, TI, SI, C] D, LL0, LL/0 Duplex
125 x 34 x 4 mm
"Pocket 259D" but actually closer to 259 with TI, SI instead of T, S, ST. Hemmi name on back of rule. Bare bamboo edges.
149A
1962-EOB
Pic
Same as 149 except celluloid veneer covers edges.
P149A
1976
Pic
LL/1, LL/2, LL/3, DF [CF, CIF, CI, C] D, LL3, LL2, LL1
Folded at π.
L, K, A [B, TI, SI, C] D, LL0, LL/0
Duplex
125 x 36 x 4 mm
All plastic. About 10 mm longer overall and 2 mm wider than bamboo 149A.

Models 150-300: Ten- and Twenty-Inch Duplex and Open Body Slide Rules
150

1925?-1932?
Pic
DF [CF, CIF, C] D
Folded at π.

K, A [B, S, T, CI] D, L

Duplex
250 mm x 1 3/16 x ¼ in
Hemmi's first duplex slide rule.  (But Hemmi called models 150, 152, 153 and 154 "Universal," not "duplex.") Copied from K&E 4088-3 whose size it exactly duplicates.
Post 1458 (1931)
Lietz 3054L (before 1932)
1932?-MIOJ
Pic
Duplex
250 mm x 1 5/8 x ¼ in
Standard (1-5/8 inch) width. Replaced by model 250.
Tamaya 4497 (1932)
Post 1458 (1932-WWII)
US Blue 1881 (--1937--)
H O 1765 (1935-MIOJ)
152
1925-48
Pic
K, A [B, CI, C] D, T
Θ, Rθ, P [Q, Q', C] LL3, LL2, LL1
Duplex
250 mm x 1 5/8 x ¼ in
"Electrical Engineer's Universal" (Duplex). Often no model number. Some marked "US Pat 1459857." (Patent issued to O D Parsons in 1923 for P, Q scales.)
Tamaya 4498 (1932); Post 1459 (c1933-WWII); H-O 1766 (-1935-48-); US Blue 1889 (1930s) Lietz (1930s)
153
1931-EOB
Pic
L, K, A [B, CI, C] D, T, Gθ
Θ, Rθ, P, [Q, Q', C] LL3, LL2, LL1
Duplex
250 mm x 1 5/8 x ¼ in
"Electrical Engineer's Universal" (Duplex). Some (c1938) with stator screws on back of rule. US Patent 2079464, May 4, 1937.
Post 1461 (c1933-WWII);
US Blue 1893 (1030s)
154
1925-69
Pic
DF, P', P [Q, CF, CI, Sθo] A, D, K
Folded at π.
Sχ, Tχ, Tθo [Th, Sh, Sh, C] D, L, χ
Duplex
500 mm x 1¾ x ¼ in
Electrical Engineer's Universal (Duplex) 20". Two cursors. Early production has scale letters eteched on cursor windows.
Tamaya 4499 (1932);
Post 1460 (c1933-WWII)
155
WWII-1951
Pic
K, A, DF [CF, B, CI, C] D, L
Folded at √10.
Sh1, Sh2, Th1 [TI2, TI1, SI1, C] D, DI
Duplex
250 mm x 1 5/8 x ¼ in
"General Engineering with Hyperbolic Scales. " Replaced by model 255.

157
WWII-1950
Pic
K, A, DF [CF, B, CI, C] D, L
Folded at √10.
LL/1, LL/2, LL/3 [TI2, TI1, SI1, C] LL3, LL2, LL1
Duplex
250 mm x 1 5/8 x ¼ in
"General Engineering with Log-Log Scales."

159
1949-52
Pic
T, DF [CF, CIF, CI, C] D, S, ST
Folded at π
LL0, LL00, A [B, K, L, C] LL3, LL2, LL1
Duplex
250 mm x 1 5/8 x ¼ in
Made to specification of F Post Co. Replaced by model 259 ("Expert Mechanical Engineer") c1952.
Post 1462H "POSTRIG"
(c1949 - 53)
160
1951
Pic
Nomogram1(α=0.05), χ2, A [B, CI, C] D, φ, ax
P, F'1 [F'2, a'] A, χ2, ,Nomogram2(α=0.01)
Duplex
250 mm x 72.5 mm
"Inductive Statistics." Almost three inches wide! Stator with nomograms is about 46 mm wide. All-plastic cursor similar to Relay/Ricoh.
165
1953
Pic



"Statistical Sampling." No slide, just many short scales and a cursor.
190
1939-42
Pic
K, A [B, R2, R1, C] D, DI
[SI2, SCI2, SI1, SCI1]
Bottom Edge: L
Closed
250 x 40 x 11 mm
"Precision Stadia." {3 hairlines: D: C, C}.
Left half of SCI1 scale is inverse cos2.
200
1936-68
Pic
D6, D5, D4 [C6, C5, C4, C3, C2, C1] D3, D2, D1
DF6, DF5, DF4 [CF6, CF5, CF4, CF3, CF2, CF1] DF3, DF2, DF1
Scales divided at 6√10.
Duplex
400 mm x 1¾ x ¼ in
"Precision Duplex." (Originally known as "Ultra Accuracy.") Four digit precision. Scales are divided into six segments, each 400 mm long. Early production has scale labels in green on cursor. U S Patent 2235106A, March 18, 1941.
201
1967-69
Pic
L2.4, L1.3, A2.4, A1.3 [C4, C3, C2, C1] D1, D2, D3, D4
K4, K3, K2, K1 [CF4, CF3, CF2, CF1] DF1, DF2, DF3, DF4
Scales divided at 4√10.
Duplex
500 mm x 1¾ x ¼ in
"Sold in Japan." Scales are divided into four segments each 500 mm long.  Early production has scale labels in green on cursor.
250
1950-EOB
Pic
DF [CF, CIF, CI, C] D, L
Folded at √10.
K, A [B, TI2, TI1, SI] D, DI
Duplex
250 mm x 1 5/8 x ¼ in
"General Engineering and Business." Replaced models 150 and 2600. About a third have anodized black end brackets.

251

1951-58
Pic
L, DF [CF, CIF, CI, C] D, DI
Folded at π.
K, A [B, T, S, ST, C] D, LL3, LL2, LL1
Duplex
250 mm x 1 5/8 x ¼ in
"Mechanical Engineer."


1958-EOB
Pic
L, DF [CF, CIF, CI, C] D, LL3, LL2, LL1 Folded at π.
K, A [B, T, S, ST, C] D, DI
H-O 1773
P253
1961-EOB
Pic
LL3, LL2, DF [CF, CIF, CI, C] D, L, LL1 Folded at √10.
K, A [B, TI2, TI1, SI] D, DI.
TI divisions= 1/12 degree
Duplex
250 x 41 x 5 mm
Vectolog." Elaborate clamshell case. All-plastic version of model 264. ¥2.400 in catalog 6911.
H-O 1774-00 (-1964);
Geotec 341-3130 (1964+)
P253 Special

1967
Pic
LL3, LL2, DF [CF, CIF, CI, C] D, L, LL1 Folded at √10.
K, A [B, TI2, TI1, SI] D, DI
Marked "P253 Special" and "Vectolog." Only difference from P253 is green CIF scale.
1965
Pic
LL3, LL2, DF [CF, CIF, CI, C] D, L, LL1 Folded at √10.
K, A [B, TI2, TI1, SI] D, DI,√3V.
Marked "P253 Special" and "Vectolog."  Short additional scale on back marked "√3V" at left and and "volt" at right end.
254W

1963-68
Pic
LL/1, LL/2, LL/3, DF [CF, CIF, CI, C] D, LL3, LL2, LL1
Folded at √10.
K, A [B, TI, SI, C] D, DI, L Duplex
250 mm x 1¾ x ¼ in.


"High School Students". Basis for model 108 demo rule. Equal length stators.
1963-72
Pic
Traditional stators.

254 W-S






1970s
Pic
Same as 254W but folded at π.
Same as 254W.
Only difference from 254W is where front scales are folded.
Only two specimens known. Date codes "RC" (March 1967) and "UB" (Feb 1970)
1969
Pic
Same as 254W. Folded at √10.
L, K, A [B, TI, SI, P] Q, Q', D, DI
With P, Q, and Q' scales
Date code "TC" = March 1969.
1970s
Pic
K, A, [SIN COS, COS2, TI, SI, C] D, DI, L
With stadia scales. Equal stators date = "OC" (Mar 1964); others = "UB" (Feb 1970) or no code.
1971
Pic
K, A [B, TI2, TI1, SI, C] D, DI, L
"High School Students." Traditional stators. Hemmi name on back of rule.
1971
Pic

Same as 254W but folded at π.
K, A [B, TI2, TI1, SI, C] D, DI, L
Date code "VC" = March 1971
1970s
Pic
KI, K, AI, A [B, S, T, CI, C] D, LdB, P, DI
May set record for number of different inverse scales on one side of a rule.
1965
Pic
LL/1, LL/2, LL/3, DF [CF, CIF, ST, CI, C] D, LL3, LL2, LL1
Folded at π.
KI, K, AI, A [B, S, T, CI, C] D, LdB, P, DI Equal length stators.

254WN
1972-EOB
Pic
LL/1, LL/2, LL/3, DF [CF, CIF, CI, C] D, LL3, LL2, LL1
Folded at √10.
LL/0, K, A [B, TI2, TI1, SI, C] D, DI, L, LL0 "High School Students." Traditional stators. Hemmi name and model number on back of rule.
254 WN-S

1972
Pic
Same as 254WN except folded at π.

1973
Pic
Same as 254WN. Folded at √10.
L, K, A, [B, TI2, TI1, SI, P] Q, Q', D, DI

255

1950-57
Pic
L, K, DF [CF, CIF, CI, C] D, χ, θ
Folded at π.
Sh1, Sh2, Th, A [B, TI2, TI1, SI, C] D,LL3,LL2,LL1
Duplex
250 mm x 1¾ x ¼ in
 "Expert Electrical Engineer." Replaced model 155.
1958-61
Pic
L, K, DF [CF, CIF, CI, C] D, LL3, LL2, LL1     Folded at π.
Sh1, Sh2, Th, A [B, TI2, TI1, SI, C] D, χ, θ

255D
1961-EOB
Pic
L, K, DF [CF, CIF, CI, C] D, LL3, LL2, LL1     Folded at π.
Sh1, Sh2, Th, A [B, TI2, TI1, SI, C] D, DI, χ, θ

256
1950-68
Pic
L/dB, Neper, DF [CF, CIF, CI, C] D, LL3, LL2, LL1
Folded at π.
A, Ĺ [Ċ, SI, TI] D, l, F
Duplex
250 mm x 1¾ x ¼ in
Electrical Communications. Ĺ and Ċ scales are about half length.
257
1952-68 Pic
L, A, DF [CF, CIF, CI, C] D, LL3, LL2, LL1
Folded at π.
Ch A-M, Ch N-Z, M1 [M2, oF, oC, oK, F(t)] Kg/cm2, mm Hg, in. Hg Vac., tω
Duplex
250 mm x 1¾ x ¼ in
"Chemical Engineer."
Post 1491 (c1957-67);
H-O 1770 (-1958-)
257L
1971-EOB
Pic
L, K, A, DF [CF, CIF, CI, C] D, LL3, LL2, LL1
Folded at π.
Ch A-M, Ch N-Z, M1 [M2, oF, oC, oK, LM] mm Hg, Kg/cm2, in. Hg Vac., tω
"Chemical Engineer." Hemmi name on back of rule.
258
1951
Pic
LL0, LL/0, K, DF [CF, CIF, CI, C] D, R1, R2, L
Folded at π.
LL/1, LL/2, LL/3 [T T, SecT ST, Cos S, C] D, LL3, LL2, LL1
Duplex
250 mm x 1¾ x ¼ in
VERSALOG Ia.  About 30 specimens marked "Hemmi 258" are known. All are also marked "THE FREDERICK POST CO. NO 1460" or "THE HUGHES OWENS CO. LIMITED NO. 1777."   Click here for a short history of model 258.
Post 1460 Versalog (1951+);
H-O 1777 Versalog (1951+).
For information about Versalog models Ib and II see the second page of this Catalogue Raisonne.
259

1950-58
Pic
L, K, DF [CF, CIF, CI, C] D, LL0, LL/0   
Folded at π.
LL/1, LL/2, LL/3, A [B, T, S, ST, C] D, LL3, LL2, LL1
Duplex
250 mm x 1¾ x ¼ in



"Expert Mechanical Engineer."  Replaces model 159.
1958-63
Pic
LL/1, LL/2, LL/3, DF [CF, CIF, CI, C] D, LL3, LL2, LL1       Folded at π
L, K, A [B, T, S, ST, C] D, LL0, LL/0
"Expert Mechanical Engineer."  Hemmi name moved to back of rule.


259D
1953-EOB
Pic
LL/1, LL/2, LL/3, DF [CF, CIF, CI, C] D, LL3, LL2, LL1      Folded at π
L, K, A [B, T, S, ST, C] D, DI, LL0, LL/0

259D-S
1970s
Pic
LL/1, LL/2, LL/3, DF [CF, CIF, CI, C] D, LL3, LL2, LL1      Folded at π.
LL0, LL/0, K, A [B, T, S, ST, C] D, √1, √2, L


260
1964-EOB
Pic
LL/1, LL/2, LL/3, DF [CF, CIF, CI, C] D, LL3, LL2, LL1     Folded at π.
LL/0, LL0, K, A [B, T, S, ST, C] D, DI, P, L
Duplex
250 mm x 1¾ x ¼ in
"Advanced Engineer."  {3 hairlines: A: C2, hp-C2}  Some rules c1970 have brand and model on bottom edge.  Some marked UNIVERSITY on bottom edge.  ¥4,800 in catalog 6911.
260 Demo
1964
Pic
LL/1, LL/2, LL/3, DF [CF, CIF, CI, C] D, LL3, LL2, LL1     Folded at π. LL/0, LL0, K, A [B, T, S, ST, C] D, DI, P, L
Duplex
1500 mm
x _
Painted wood classroom demonstration  rule.  Cursor is single wire.

P261
1965-EOB
Pic
LL01, LL02, LL03, DF [CF, CIF, CI, C] D, LL3, LL2, LL1
Folded at π.
T, ST, K, A [B, BI, CI, C] D, L, P, S Duplex
250 x 46 x 5 mm
"Advanced Engineer" (Darmstadt).  Stators white or pale blue.  {4 hairlines on back of cursor. A: C2, hp-C2, D: C}
T-P 1420 (c1971 only)
T-P 44CB-200 (1972+)
Geotec 341-3660
P262 1965-EOB
Pic
LL01, LL02, LL03, DF [CF, CIF, CI, C] D, LL3, LL2, LL1     Folded at π.
K, A, R1, R2 [T2, T1, ST, S, C] D, L, LL00, LL0
Duplex
250 x 46 x 5 mm
"Advanced Engineer" (Rietz).
T-P 1422 (c1971 only),
T-P 44CB-220 (1972+)
P263
1964-69 Pic
P1, P2, DF [CF, CIF, CI, C] D, LL, LL    Folded at 360. A, N [M, £, S/d, C] D, G
Duplex
250 x 41
x 5 mm
"Commerce."  N, M have 365 divisions for dates.  £,S/d = pound, shilling/pence.   G is a set of conversion gauge marks Geotec 341-3155 (1967+)
Hemmi 143 is pocket version.
264
1968-EOB
Pic
LL3, LL2, DF [CF, CIF, CI, C] D, L, LL1      
Folded at √10
K, A [B, TI2, TI1, SI] D, DI.    
Duplex
250 mm x 15/8 x ¼ in
Bamboo version of model P253, Vectolog.

264-S
1969
Pic
K, A [B, TI, SI, P] Q, D, DI
P & Q scales, Single TI scale.

264-M

Pic
K, A [B, TI2, TI1, SI] D, DI.   
A mis-marked model 264?  Only known specimen was sold on Yahoo Japan, June 2018.  Photo shows factory marking  "264-M."  
264-S
1970s
Pic
LL3, LL2, DF [CF, CIF, CI, C] D, LdB, LL1    Folded at √10.
K, A [B, TI2, TI1, SI]  D, DI, χ, θ


P265
1968-72
Pic
P1, P2, DF [CF, CIF, CI, C]  D, LL2, LL1    Folded at 360
A, D [G,  0-24, N]  M, 0-24
Duplex
250 x 46
x 4 mm
"Business."  N, M have 365 divisions for dates.   G is a set of conversion gauge marks.  Instructions & scale labels in Japanese.
266
1961-EOB
Pic
(LL/3 and LL/1), LL/2, LL2, A [B, BI, CI, C] D, dBL, S, T
XL, XC, F, (τ1 and P),  [(τ2 and Q), L, C, Cz] L, Z, fo
Duplex
250 mm 
x 1¾ x ¼ in
"Electronics."  Announced in 1961 but not in Hemmi catalogs until 1966.  Early specimens (1962) marked "Developed by SONY."  LL/3, LL/1, τ1, τ2, P, Q are partial length scales.  Also sold as Geotec 341-3550 (1966+) 
P267
1971-EOB
Pic
³√-3,  ³√-2, ³√-1, DF [CF, CIF, CI, C]  D, √-1, √-2, δ(unif.)
Folded at √10
4√-4, 4√-3, 4√-2, 4√-1 δ(conc)λδ(Trape)λM,  P] Q, L, T, S
Duplex
250 x 46 x 5 mm
"Structural Design."

269
1965-EOB
Pic
L, F, K, A [B, K', CI, C] D, LL3, LL2, LL1
CL, SL, M, TL [R, ST, T, S, C] D, DI, SinCos1, SinCos2
Duplex
250 mm x 1¾ x ¼ in

"Civil Engineer."

P270
1971-EOB
Pic
J, J [T(ºK), Q(m³/s), Q(m³/s)]  Hm(m), Q(m³/s), Ht(m)
X, X, Cz, Cmax(PPM)  [He(m), Cy, CI, C] D, A, L
Duplex
250 x 46 x 5 mm

"Pollution A."  (air quality analysis)  19 scales in black, red and blue.
P271
1974
Pic
x,xs(g/kgDA), (ice)Tφ,tφ(ºC) [hw,hs(mmhg), CI, C] D, v, va(m3/kgDA), t(ºC), t(ºF)
[t(ºC)(ice), t'2.5t(ºC)]
Open
250 x 46 x 5 mm
Moist air.  There are 13 scales--most with complicated labels.

274
1973-EOB Pic
L, DF [CF, CIF, CI, C]  D, LL3, LL2, LL1
Folded at √10
K, A [B, TI2, TI1, SI, C]  D, DI
Duplex
250 mm x 1¾ x ¼ in
Late model general engineering rule with scales folded at √10 and trig scales inverted.  Likely sold only in Japan.
274-S

Pic
K, A [B, TI2, TI1, SI, C]  D, DI, dB

NA
dB, K, A [B, TI2, TI1, SI, C] D, DI, χ, ϴ

275

1950-58
Pic
L, K, DF [CF, CIF, CI, C] D, χ, θ   
Folded at π.
Sh1, Sh2, Th, A [B, TI2, TI1, SI, C] D, LL3, LL2, LL1
Duplex
500 mm x 1¾ x ¼ in
20-inch Version of Model 255.
1958-63
Pic
L, K, DF [CF, CIF, CI, C] D, LL3, LL2, LL1      Folded at π.
Sh1, Sh2, Th, A [B, TI2, TI1, SI, C]  D, χ, θ
20-inch Version of Model 255. Some with green scale labels on cursor.

275D
1963-69
Pic
L, K, DF [CF, CIF, CI, C] D, LL3, LL2, LL1    Folded at π.
Sh1, Sh2, Th, A [B, TI2, TI1, SI, C]  D, DI, χ, θ
20-inch Version of Model 255D. Some with green scale labels on cursor.

279

1950-58
Pic L, K, DF [CF, CIF, CI, C] D, LL0, LL/0        Folded at π.
LL/1, LL/2, LL/3, A [B, T, S, ST, C] D, LL3, LL2, LL1
Duplex
500 mm x 1¾ x ¼ in
20-inch Version of Model 259.  Some with green scale labels on cursor.
1958-63
Pic
LL/1, LL/2, LL/3, DF [CF, CIF, CI, C] D, LL3, LL2, LL1    Folded at π.
L, K, A [B, T, S, ST, C] D, LL0, LL/0

279D
1963-69
Pic
LL/1, LL/2, LL/3, DF [CF, CIF, CI, C] D, LL3, LL2, LL     Folded at π.
L, K, A [B, T, S, ST, C] D, DI, LL0, LL/0
20-inch Version of Model 259D. Some with green scale labels on cursor.

P280
1959-72
Pic
T, K, A [B, CI, C] D, L, S, ST
[LL1, LL2, LL3]
Open
250 x 46 x 4 mm
"Beginners."
T-P 1414 (c1971 only), 44BB-140 (1972+); Geo 341-3645; Ahrend P280.
280S
1976?
Pic
L, K, A [B, CI, C] D, S, ST, T
cm
[LL1, LL2, LL3]
inches
Open
250 mm
All plastic.  Marked "HEMMI, JAPAN, 280S" but probably made by D&P.  Only known specimen found in Thailand
Ahrend P281;
Same as Aristo 0903 except back of Aristo slide is blank.
P281
1970-72
Pic
T, K, A [B, CI, C] D, L, S, ST
Blank
Open
250 x 46 x 4 mm
Rietz. T-P 1410 (c1971 only), 44BB-100 (1972+);
Geo 341-3640
P283
1970-71
Pic
K, A, DF [CF CI, C] D, L, T, S
Folded at π.
[LL1, LL2, LL3]
Open
250 x 46 x 4 mm
Beginners.
Ahrend P283.
Models 300-999: Specialty Slide Rules
300
WWII  Pic
G, E [F, CI, C] D, M
[Blank]
//Closed||
250 x 34 x 8.5 mm
Decimal Calendar Rule.  G scale is folded at 365; E & F folded at 3.042 = 365/12.  M scale is set of gauge marks for Japanese weights & measures. Japanese language.
301
301A

1954-69
Pic
τ, ω [CI, f, P, C] D, A, db
[θ, θd, g', g]
//Closed||
250 x 34 x 11 mm
Control Engineering.  Four cursors!  301A is 301 plus a transparent overlay.
Post 1490 (1957-ca67)
305
1959-70
Pic
TmV/S, ℓ1 [ℓ2, m, a] T, v
[N, F, u]
//Closed||
125x26 x _ mm
Acoustic Design.  Patents 225936, 225937.
400
1959-68
Pic
Y, A [B, CI, C] D, LL3, LL2, LL1
Eß, R(AI), Dist, Dose Rate [S, Isotopes (4 scales)] Ev, Pb, Fe, Al
Duplex
250 mm 
x 1¾ x ¼ in
Radioisotope Engineering.

401
1966-69
Pic
d, W [Nt, D, MI, M]  L
τo, P [d, D, D, Na(δ)]  k(P), d
Duplex
250 mm 
x 15/8 x ¼ in

"Coiled Spring Rule."

P402
1966-69
Pic
15 scales in black, red, blue and green -- all labeled in Japanese.  Only three scales are full length.  Scale arrangement and range of variables differs slightly between the two models. A, DF [CF, CIF, CI, C] LL (2 scales)
Folded at √10.
Duplex
250 x 41 x 5 mm

"Tanabe Corporate Performance Analysis."  P402 for manufacturing businesses; P403 for wholesale and retail distributors.  Rule and instructions in Japanese. Click here for an illustrated explanation of models P402 and P403 by Atsushi Tomozawa.
P403
1966-69
Pic
405
1950-68
Pic
C2F, Al2O3 [Fe2O3, C2AF]  C2A, SO3, CaSO4
C2S (A Scale), CaO [SiO2(for C3S), Fe2O3, SiO2(for C2S), SO3/Al2O3]  C3S, C2S (B Scale)
Duplex
250 mm 
x 1¾ x ¼ in
"Cement Composition."  Scale labels are chemical symbols, numbers subscripted.  No scales are logarithmic. Fe2O3 and SiO2(for C2S) are separate short scales on same line.  Accompanying Instruction Manual published by Portland Cement Assoc. Skokie, Ill, May 1959. 
410
1959-69
Pic
G2, G1, F2, F1 [x, F1G1]  Z1+Z2, G', F'
G2, G1, F2, F1 [x, CI, C]  D, A
Duplex
250 mm 
x 1¾ x ¼ in

"Involute of Gear Wheel."

451
1969
Pic
Eight specialized scales.  Center scales are not full length.
LL/3, LL/2, LL2, A [B, BI, CI, C]  D, dBL, S, T
Duplex
250 mm
"Field Intensity."
There are bamboo and all-plastic versions of this rule; both are marked "451."  (Not "P451") 
P452
1968-72
(For Post)
Pic
LL1, LL2, LL3, CR_DF [T_CF, CIF, %_CI, T_C] R_D, L, in, cm       Folded at π
ST, 3n-2_K, 2n-1_A [B, BI, CI, C] D, P, S, T
Duplex
250 x 46 x 4 mm
"Business."  Some marked "System H. Kroon."  Yellow slide, green brackets.  (Post & T-P have blue slide & brackets)
T-P 1426 (c1971 only), 44CB-260 (1972+)
500
1943
NA


125 mm 
x _
"For Airplane."  ¥8.50 in 1943 price list.  No other mention.

640S
1972
Pic
K, DF [CF, CIF, CI, C] D, A, L    
Folded at √10.
[STI, TI2, TI1, SI, CI]
//Closed||
250 x 45 x 9 mm
Desk Rule.    Bamboo between thick plastic

641
1975
Pic
K, A, DF [CF, CIF, B, CI, C] D, DI, L   Folded at √10
[STI, TI2, TI1, SI, CI]
//Closed||
250 x 45 x 9 mm
Desk Rule.   Bamboo between thick plastic.

642T
1973
Pic
K, A [B, BI, CI, C] D, DI, L      
with over-range
[T2, T1, ST, S]
//Closed||
250 x 45
x 9 mm
Desk version of 64T. Bamboo between thick plastic. 
{3 hairlines: D: C, C}.
Ahrend 643T
651
1969
Pic
K, A, DF [CF, CIF, B, CI, C] D, DI, L
Folded at √10.
[TI2, TI1, STI, SI, C]
//Closed||
250 mm x 1½ x 7/16 in


Models 1xxx: Circular Slide Rules
1001
1971
Pic
A, D, C, CI, L
Blank
Circular
80 mm
Circular.
    Geotec 341-3910
1002
1971
Pic
A, D [C, CI]
Blank
Circular
80 mm
Circular.  Less elaborate than 1001.

2600 Series Rules Introduced in 1940 (February 11, 1940 was the 2600th Aniversary of the Founding of Japan) 
2600
1940-51
Pic
DF [CF, CI, C] D, L
Folded at √10.
K, A [B, TI2, TI1, SI1] D, DI
Duplex
250 mm 
x 15/8 x ¼ in

General Engineering and Business.

2634
1949-EOB
Pic
K, DF [CF, CI, C] D, A
Folded at √10.
[TI2, TI1, L, SI]
//Closed||
125 x 26
x 5 mm
Pocket 2664.

P2634

Pic
K, DF [CF, CI, C] D, A
Folded at √10.
[TI2, TI1, L, SI] ||Closed||
125 mm
x _


2640
1949-68
Pic
ℓ, A [B, CI, C] D
[S, K, T]
(S keyed to C/D)
||Closed||
200 x 28
x 8 mm
Beginners Slide Rule for 50W.  Plastic cursor.

2641

Pic
DF [CF, CI, C] D, A
Folded at √10.
Blank
||Closed||
200 x 28
x 8 mm
Beginners Slide Rule for 45 (which, itself, was a beginner's rule).  Plastic cursor.

2645
WWII
Pic
DF [CF, CI, C] D, A
Folded at √10.
[TI, L, SI]
Closed
200 x 28 x 8 mm
Essentially identical to model 45 except CI scale is black.
Only one specimen known.
2662
1966-69? Pic
K, A, DF [CF, CIF, CI, C] D, DI, L
Folded at √10.
[B, TI, SI, C] //Closed||
250 x 34
x 11 mm
Some with 13-0-13 cm scale on bottom edge. See Hemmi Catalogue Raisonne 2 for a slide projector version of this rule.
2664 WWII
Pic
K, DF [CF, CI, C] D, A+L
Folded at √10.
[TI1, TI2, SI2, SI1] ||Closed||
250 x 34
x 9 mm
Wartime construction (bare vertical edges and back)  No model number on rule.  A+L scale is left half of A scale joined to right half of L scale.
MIOJ
Pic
K, DF [CF, CI, C] D, A       Folded at √10.
[TI2, TI1, L, SI1]
//Closed||
250 x 34
x 11 mm
Better quality construction.  Full length A scale; L scale replaces SI2. 
1949-58
Pic
K, DF [CF, CI, C] D, A+L    Folded at √10.
[TI1, TI2, SI2, SI1]
A+L scale is left half of A scale joined to right half of L scale.

2664S
1958-69
Pic
K, DF [CF, CIF, CI, C] D, A               Folded at √10.
[TI2, TI1, L, SI]
//Closed||
250 x 34
x 11 mm
Same as 2664 except 10 mm longer overall and green CIF scale added.
¥2,200 in catalog dated 6911
2664S-S
1967
Pic
K, A, DF [CF, CIF, CI, C] D, DI
Folded at √10
[TI2, TI1, L, SI]
//Closed||
250 x 34
x 11 mm
Same as 2664S except DI scale added.

2670
MIOJ
Pic
K, A [B, CI, C] D, L
[S, S&T, T]
//Closed||
500 x 40
x 12 mm
Long Rietz.  Short-lived replacement for model 70.  {3 hairlines: D: C, C}.

2690
1951-68
Pic
L, D [M1, M2, C] D, A
[S, S&T, T]
//Closed||
250 x 34
x 11 mm
Stadia.  {3 hairlines: D: C, C}.

2690A
1954-55
NA
Same as 2690 "2690A" marked on case to distinguish model 2690 from proposed centesimal degree model 2690B.  Rules are marked just "2690."  
Odds and Ends
P3526
1970s?
Pic
S, K, A [B, CI, C] D, L, T
None
||Closed||
250 x 40
x 3 mm
Beginner's all-plastic slide rule marked "HEMMI, Japan, NO P3526"  but manufactured by Hope Slide Rule Mfg Co, Tokyo.  Same as Hope model 51.  (The only known 'Hemmi' example was found in New Zealand.)








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