Quarth (クォース, Kwōsu) is a hybrid puzzle game/shoot 'em up developed by Konami which was released in 1989 as an arcade game, sold as Block Hole outside Japan.

Besides the arcade version, there were also ports of the game to the MSX2 (with a built-in SCC chip), Famicom, and Game Boy—home releases used the Quarth name worldwide (with the exception of the Game Boy Color release in Europe of Konami GB Collection Vol. 2, where the game was renamed to the generic title Block Game for unknown reasons).

Quarth was released on the Konami Net i-mode service as Block Quarth, with an updated Block Quarth DX in 2001. It was released without the "DX" suffix in 2005, and was made globally available through Konami Net licensing on many i-mode services offered by mobile operators. In Europe, for example, it was available from O2 UK, O2 Ireland, and Telefónica Spain.

In 2005, Konami also included the game in the Nintendo DS title Ganbare Goemon: Tōkai Dōchū Ōedo Tengu ri Kaeshi no Maki. An emulated version of the game was released in 2006 for PlayStation 2 in Japan as part of the Oretachi Geasen Zoku Sono-series.