Hammerin' Harry, known in Japan as Daiku no Gen-san (大工の源さん), is a series of platforming video games developed and published by Irem in 1990. The titles were developed and published for the arcades, NES, Game Boy, Famicom and Sony PSP platforms.
The first spin-off in the series was Kizuchida Quiz da Gen-san Da! (木づちだ クイズだ 源さんだ!), a quiz game released for the Game Boy on December 19, 1992 exclusively in Japan. Others were various Japan-only, pachinko machines, as well as home ports of them for Sony PlayStation, PlayStation 2, Windows-operated PCs and Game Boy. Outside of the franchise, Hammerin' Harry was represented in a Japan-only Game Boy title, Shuyaku Sentai Irem Fighter along with three other Irem franchises: R-Type, Ninja Spirit and Mr. Heli. Hammerin' Harry can be seen on the arcade flyers of Ninja Baseball Bat Man, also by Irem.
On March 24, 2008, an anime series based specifically on the PSP title Hammerin' Hero, titled as Ikuze! Gen-san (いくぜっ!源さん), was aired on GyaO's website until June 9, 2008. There were 24, 9-minute webisodes aired. A DVD compiling the episodes was released in April 2009.