The Tsuranuki Zutsu (ツラヌキ筒) is a weapon created to pierce the iron hearts of Kabane more efficiently than conventional steam weaponry, invented by Ikoma and Takumi. A combination of high pressured steam injected into a cartridge of gunpowder creates a needle-like explosive reaction that can bore through both cage and heart of a Kabane with ease, although at the cost of its nearly nonexistent range; the gun has to be fired at point blank, something that few people dare attempt and cost Ikoma his humanity. The main concept came from a simple steamsmith's rivet gun, possibly upscaled and weaponized to the point that it could be used against Kabane.
Before completing the Tsuranuki Zutsu, Ikoma described this device as using "Jet bullets" which produced more penetrating power than ordinary lead shots.
The Tsuranuki Zutsu was designed and developed by Ikoma and Takumi and as of yet only a single one has been made. However, given that it has been made by just two steamsmiths, given the right materials additional units could be produced.