GMCA YouTube page here has a variety of videos: matches, informational videos, interviews, demonstrations, and short clips.

A basic overview of the world of Japanese soroban is available here. GMCA also offers a Japanese soroban rating test simulator here.

Practice simulators available here and competition app available here.

If you are looking for practice guides, WorldMentalCalculation includes guides for approaching certain competition-style formats.

Registration Open for Season 3 Now

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Registration Open for Season 3 Now 〰️

Global Mental Calculators Association:

Mental Calculation League

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Two Seasons per year: Spring/Summer and Fall/Winter

Match videos available here and on GMCA Youtube page.

Season 2 concluded on April 26! Here are links to: Results, Standings, and Season Statistics.

Please visit “Mental Calculation League” section to Register for Season 3 (estimated to begin in May 2025) and for more information.

Practice “league simulator,” as well as other calculation simulators, are available here. The Calculation League app —with FAQ and an instructional video — is available here.

Jeonghee Lee
Aaryan Shukla
Wenzel Gruss
Master Lee Teaching

Board Members