"Kaiketsu Yanchamaru: Ghost Building Company" is a side-scrolling action game developed by Irem and released for the Game Boy on July 31, 1992. The story follows foreman Yanchamaru, whose girlfriend Konna is kidnapped by a giant ghost. To rescue her, Yanchamaru bravely infiltrates the haunted Ghost Building Company and battles all manner of specters. Players control Yanchamaru, wielding a wooden hammer to defeat enemies. Some foes drop items such as hard hats, screen-clearing tools, and health recovery pickups. Two weapon upgrade items are also available: one transforms the hammer into a spinning attack, while another enlarges it into a chain-ball to enhance striking power. Compared to the Famicom version, the swing speed is slightly slower, getting hit causes status drops, and invincibility time is shorter. The first Game Boy entry in the Yanchamaru series features large character sprites, cleverly designed stages, and music that fully leverages the GB's stereo capabilities, offering challenges comparable to the FC version. In 2020, the Advance and DMG translation groups jointly released a Simplified Chinese localization, allowing more players to enjoy this classic title.