Kusari

is an eroge visual novel by Leaf. It is a suspense adventure game dealing with psychological warfare as players are pitted against a cunning and powerful criminal while trapped in the open sea on a cruise ship.

Although this game produced Leaf, much of the staff for this game was outsourced. This was because the game was outside of the fantasy or true love scenario games that have become the company's backbone. Instead the game had twisted dark scenarios.