In 2005, the American Go Honor Society established the SO Cup as a means of another series, conceived in the minds of former US proconsul, Christopher Vu and former Canadian proconsul Adrian Petrescu, as an individual tournament series in contrast to the highly successful K-12 National Team Go Championships held in the United States, Canada, and France.

The intent was to establish the first title tournament seris in North America, that would follow the same rules seen in professional title tournaments in Asia. In order to broadcast towards the youth, an age limit was imposed to promote the tournament series to a younger audience for the goals of the American Go Honor Society and the Canadian Go Honor Society.

In August of 2005, the tournament was re-named the Kato Masao Memorial Tournament to honor a legendary figure and organizer in the go community, Kato Masao of Japan.