Abacus checkers - Wikipedia

The Abacus Rhapsody in Numbers

Frontiers Iconic Mathematics: Math Designed to Suit the Mind

History of Abacus and Ancient Computing - KASS

List of abstract strategy games - Wikipedia

Which is a better game, chess or checkers? - Quora

An Introduction to the Traditional Abacus of China and Japan

History of Abacus and Ancient Computing - KASS

History of Abacus and Ancient Computing - KASS

How to Play Go – Yellow Mountain Imports