NScripter is an engine for the creation of visual novels, written by Naoki Takahashi. Due to its simplicity and its liberal license (while it is not open source, royalty-free commercial use is permitted), it quickly became popular in Japan, and was used for a number of high-profile commercial and dōjin titles, such as HaniHani and Tsukihime. ONScripter is a popular development branch that has an english language version.
Tool Classification:
Functions=
(Engines - Interactive Fiction)
Qualifiers=
(Mac OS version available) (Linux version available) (Console engine/support)