During development of the AA gun tank, the Imperial Japanese Army experimented with various configurations. This single gun prototype was designated the Type 98 Ta-Se self-propelled anti-aircraft gun. Initial development began in November 1941.^[1][2] The name was taken from taikū ('anti-air') sensha ('tank'). The conventional turret was removed from the hull and a new open-top cylindrical shaped turret was installed. It was equipped with a single converted Type 98 20 mm AA machine cannon. During trials, it was determined that the chassis used for the Ta-Se was too small to be a stable "firing platform".^[1][2] It did not enter production.^[2]

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  Front view of Type 98 Ta-Se
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  Side angle view of Type 98 Ta-Se

After the Type 98 Ta-Se SPAAG was abandoned, a second prototype version, known as the Type 98 20 mm AAG tank was produced using the Type 98 chassis. The gun tank was equipped with a modified twin Type 2 20 mm AA machine cannon mounted on a raised platform with a gun shield. It also did not enter mass production after testing.^[1][2]

Prior to the Type 98 Ta-Se, an earlier prototype was produced that was known as the experimental Type 97 Ki-To self-propelled anti-aircraft gun. The original Type 97 Te-Ke tankette turret was removed, and a single Type 98 20 mm AA machine cannon was mounted on the modified chassis without a protective gun shield.^[3] It did not enter production.

• Type 98 20 mm AA half-track vehicle
• 20 mm AA machine cannon carrier truck

• Taki's Imperial Japanese Army Page - Akira Takizawa
• Tomczyk, Andrzej (2007). Japanese Armor Vol. 5. AJ Press. ISBN 978-8372371799.