PaintTool SAI

PaintTool SAI or Easy Paint Tool SAI (ペイントツールSAI) is a lightweight and painting software for Microsoft Windows developed by Koji Komatsu (小松 浩司, Komatsu Kōji) and published by Systemax. The prototype of the software was "Full Color Paint Tool -Sai-" (フルカラーペイントツール-彩-, Furukarā peinto tsūru -Sai-) for X68000, produced in October 1996; Development of the software began on August 2, 2004, with an alpha version released on October 13, 2006, a beta version on December 21, 2007, and a commercial version (1.0.0) on February 25, 2008. It has been available on Microsoft Windows from XP to 11. A version 2 is in development as of 2026.