In September 1923, he was appointed as military attache to Riga in Latvia, and afterwards was assigned to Germany, returning to Japan in August 1927.

In March 1941, Shimizu was assigned command of the IJA 41st Division, which was at the time a garrison force based at Qingdao, China.

However, in July 1942 he was reactivated to become Deputy Inspector-General of Military Training, one of the top posts within the Imperial Japanese Army.

This was a new field army raised under the Southern Expeditionary Army Group for the specific task of opposing landings by Allied forces in Japanese-occupied Malaya, Singapore, Borneo, Java, and Sumatra, as well as to consolidate a new defense line after the loss of the Solomon Islands, New Guinea and eastern portions of the Netherlands East Indies.

By the time he reached Manchukuo, much of its equipment and experienced troops had already been redirected to other commands in the Southeast Asia theatre of operations, and its poorly equipped and poorly trained forces were no match for the experienced battle-hardened Soviet armored divisions in the Soviet invasion of Manchuria.