Type 4 75 mm AA Gun — Japan’s Captured‑Bofors Copy (1944) Japan’s Type 4 75 mm AA gun was an Imperial Japanese Army anti‑aircraft gun that entered production in 1943 and was accepted in 1944 (Type “4” = imperial year 2604 / 1944). It was essentially a reverse‑engineered copy inspired by captured Swedish Bofors M29 75 mm AA guns taken from Chinese forces, because Japanese evaluators considered the Bofors design superior to the existing Type 88 75 mm AA gun. But the Type 4 arrived when Japan’s ind

In focus: the Bofors 40mm Mk 4 gun that will equip the Type 31 frigates - Navy Lookout