There is another hypothesis that ancestors of the Tokimasa were of a powerful family with real connections in the imperial capital and that an ancestor a few generations back had married into a local ruling family in Izu, whereby the HOJO clan was established.
その一方で、都で一定の官位を有していたが時政の数代前の先祖が婿入りして伊豆で北条氏を起こした都とのつながりを有する有力な豪族であったとの説もある。