Jump Square (ジャンプスクエア, Janpu Sukuea, often written as Jump SQ.) is a Japanese monthly shōnen Manga magazine with a circulation of over 500,000. Published by Shueisha, the magazine premiered on November 2, 2007 as a replacement for Monthly Shōnen Jump, another manga anthology that Shueisha discontinued in June. The magazine is a part of the Jump line of magazines The manga titles serialized in the magazine are also published in tankōbon volumes under the Jump Comics label.
In the context of Bakuman, SQ is run by Editor in Chief Masahiko Ibaragi. It is somewhat depicted as the pool for rejects of Weekly Jump. Such is the case with Koogy, whose manga Colorfusical places 14th in the run for the Treasure award, yet manages to get serialized nonetheless.