BW-Joseki is a free Android application developed by Marc Oldenhof, designed to provide a simple and convenient way to view Kogo's Joseki Dictionary, the well-known opening book for the game of Go, also known as Baduk or Weiqi. With its latest version, the app offers a range of features to enhance the user experience.

The app contains the latest version of Kogo's Joseki Dictionary, and allows users to perform horizontal, vertical, and diagonal transpositions with a single touch. Users can also switch player colors, with comments updated automatically with each transposition and color switch. Additionally, on phone screens, users can enlarge the comment field by clicking on it, while the Tether feature allows for accurate stone placements even on small screens.