It is said that with entering into the Kanto Region, the tatami craftsmen in the Mikawa Region inevitably moved to Edo and produced the tatami of 'inaka-ma,' which later became the standard.
家康の関東入部に伴い、三河地方の畳職人も江戸に移り、必然的に江戸でも「田舎間」の畳を作り、それが標準となったという。