1941 Infantry Division (square), Imperial Japanese Army, 8.12.1941

This depicts a typical organization. Actual organizations and equipment could vary from unit by unit. The square (four infantry regiment) infantry division was being gradually phased out by late 1941. On paper, this type of division had about 25,000 men. But the divisions were seldom as neat and tidy as the diagram above. Elements were consistently being attached or detached, so that some divisions had as few as 17,000 men and some as others as many as 32,000.

Also the divisions' own units did not not always have the same size or configuration. A typical example would be the cavalry "regiment". In some divisions (such as in the diagram above) this was a battalion sized unit of horse cavalry, in others it was a motorized unit with its own light tanks, [see Infantry Division (triangular)], or various combinations thereof. For example, the 5th Reconnaissance Regiment had 2 motorized infantry companies, 1 motorized HMG company, 1 motorized antitank company, and 2 tankette companies.

The artillery also suffered variations - in one case (19th Infantry Division) even having two regiments - some being equipped with different types and numbers of guns. The size of the Transport Regiment also tended to vary, depending on the mission assigned to the division, and whether the regiment itself was horse-drawn, partially or wholly motorized. For example, the transport "regiment" of the 18th Division had one horse-drawn company and three truck companies.

In the process of converting these divisions to the triangular (three infantry regiment) Organization, one brigade headquarters and an infantry regiment, (with the appropriate support units), might be withdrawn from the division and operate indepndently.

Infantry Divisions (Square)
Division Commanding General	Infantry				Artillery			Recon "Rgt"	Engineer "Rgt"	Other Units	Notes
Division Commanding General	Brig	Rgts	Brig	Rgts	Hqs	Rgts	Equipment	Recon "Rgt"	Engineer "Rgt"	Other Units	Notes

3 LTG Fusataro TOYOSHIMA	5	6 68	29	18 34	–	3 Fld	36x 75	3 Cav	3	3
5 (motorized) LTG Masao WATANABE	9	11 41	21	21 42	–	5 Fld	24x 75 12x 105	5 Recon	5	5	(1)(3)
13 LTG Eitaro UCHIYAMA	26	58 116	103	65 104	–	19 Mtn	36x 75	13 Cav	13	13
18 (motorized) LTG Renya MATAGUCHI	23	55 56	35	114 124	–	18 Mtn	36x 75	22 Recon	12	18	(2)(3)
19 LTG Yoshio KOZUKI	37	73 74	38	75 76	19	15 Fld 25 Mtn	8x 150 36x 75	19 Recon	19	19
20 LTG Hisashige NAGATSU	39	77 78	40	79 80	20	26 Fld	36x 75	20 Recon	20	20
110 LTG Mamoru IINUMA	108	139 140	133	110 163	–	110 Fld	36x 75	110 Cav	110	110
116 LTG Toshijiro KEUCHI	119	109 120	130	133 138	–	122 Fld	36x 75	120 Cav	116	116

Notes: (1) But: 2nd Epidemic And Water Supply Department. Included the Tank Unit, 5th Division. (2) 35th Infantry Brigade with 124th Infantry Regiment operated independently as "Kawaguch1 Detachment", and was still at Camranh Bay. (3) Only the 5th and 18th divisions were "motorized" square divisions, being equipped with 500 trucks each. The trucks were for the heavy equipment and the artillery, whereas every soldier not riding in a motor vehicle rode a bicycle.