According to
a U.S. Army manual, the Type 89 fired a 50mm round, and weighed ten pounds. Depending on the round used, it had a maximum range of just under 750 yards. It could fire incendiary rounds, smoke rounds, and high-explosive rounds. Think of it as kind of an M79 grenade launcher on steroids.
Two Marine Corps legends, "Chesty" Puller and Merritt Edson, both came away very impressed by this weapon. Edson, who lead the Marine Raiders on Guadalcanal, noted that a Japanese soldier could carry that weapon and ten rounds with no problem.
The weapon was issued in large quantities to Japanese troops and had a high rate of fire. As a result, it was believed to have caused 40 percent of American battle casualties in the Pacific.