The Type 91 surface-to-air missile (91式携帯地対空誘導弾, 91-shiki Keitai Chitaikū Yūdōdan) is a Japanese man-portable air-defense system (MANPADS). Its appearance is similar to the US-made FIM-92 Stinger anti-aircraft missile.

Hiro Type 91 (engine), a 12-cylinder aircraft engine used by the Imperial Japanese Navy in the mid-1930s; Type 91 grenade, an improved version of the Type 10 hand grenade of the Imperial Japanese Army; Type 91 10 cm howitzer, used by the Imperial Japanese Army during the Second Sino-Japanese War and World War II

The Nakajima Type 91 fighter was a Japanese fighter aircraft of the 1930s. It was a single-engine, single-seat parasol monoplane with a fixed, tailskid undercarriage.

九一式重型坦克（英文：Type 91 Heavy Tank，又称：91式重战车），用于伴随引导掩护步兵，是日本第二次世界大战最初开发的一型重战车。 该型坦克是以一式坦克为基础研发，只制造了一辆样车，未投入批量生产。

In 1931 the first entirely Japanese-production fighter went to the army, the Nakajima Type91. The specification had been issued in 1927 and after the prototype had been initially refused the military authorities had reversed their decision and had accepted the aircraft with some changes.

Two fighters and a reconnaissance aircraft were destroyed on the ground in an uprising of Chinese soldiers. Nakajima Army Type 91 Fighter seemed to be the most common type of fighter in Manchukuo Imperial Air Force at that time.

The Type91 Vehicle-Mounted Light Machine Gun 「九一式車載軽機関銃」was the main Japanese tank machine gun used from 1931 to 1937. It was a slight modification of the Type11 Light Machine Gun. The gun was equipped with a 1.5x magnification scope ranged at 300 meters. This scope could not be mounted with the standard Type11.

There is some evidence that a modified 36 cm and 46 cm Type 91 AP projectile, called the Type 1, with a slightly longer and more pointed windscreen and a single wide British-style driving band – similar to pictures of known experimental 48 cm AP projectiles that were tested during World War II – was introduced at some time during World War II, b...

The Type 91 was an aerial torpedo of the Imperial Japanese Navy. It was in service from 1931 to 1945. It was used in naval battles in World War II and was specially developed for attacks on ships in shallow harbours. The Type 91 aerial torpedo had two unique characteristics.

2017年4月6日 · The Type 91. The first prototype of this heavy tank was built in 1931 and was designated the Type 91. This was an 18-ton vehicle, powered by a 6-cylinder BMW IV inline engine that ran on gasoline. The engine was likely purchased from Germany.