abstract:is a Japanese visual novel developed by Haikuo Soft, and was originally released as an erotic game on January 27, 2006 for the PC as a limited edition containing a set of three CD-ROMs in Japan, followed by the regular edition, released on September 1, 2006 as a DVD for the PC. A PlayStation 2 version titled Yotsunoha: A Journey of Sincerity, published by Gadget Soft with adult content removed, was also released on August 28, 2008.