The Ooku (大奥) of Edo Castle was known as a womens' quarters, strictly off-limits to anyone other than the Shogun (将軍). However, some male officials did work in specific areas near the entrances.

Among those tasked with security was a group known as the ‘Igamono (伊賀者),’ said to have rescued Tokugawa Ieyasu (徳川家康) from a perilous situation during the Sengoku (戦国) period. The Igamono were ninjas (忍者) originating from Iga (伊賀) Province (Iga no Kuni, modern-day western Mie Prefecture), familiar from popular media such as the manga series Ninja Hattori-kun (忍者ハットリくん).

江戸城の大奥。そこは、将軍以外は立ち入ることのできない女の園……ではありますが、実は出入口近くの一部エリアには男性の役人たちも勤めていました。

警備を担当する役職には、戦国時代に徳川家康のピンチを助けたという「伊賀者（いがもの）」の名が。伊賀者とは漫画『忍者ハットリくん』でもおなじみの、伊賀国（いがのくに、現在の三重県西部）出身の忍者のことです。