Jirō Saemonsaburō (佐衛門三郎 二朗) is a blacksuit part of the group Tonegawa manages in the spin-off series Chuukan Kanriroku Tonegawa.

He is known for being one of the youngest in the group and for his knowledge in handling modern technology such as creating Powerpoint presentations. He also tutored Tonegawa in twitter.

He is credited for inventing Restricted Rock, Paper, Scissors and it was his idea to host it on the Espoir.


Saemon is one of the more practical and intelligent members of Tonegawa's team. For example, he was the only one to turn down Human Mahjong due to finding it impractical.


At one point, he convinces the blacksuits (save Yamazaki) to change their appearance a bit, but was foiled by Tonegawa.

He also aids in capturing Ebitani after he anonymously posts negative comments about Teiai on Twitter.


  • Tonegawa thinks his full name sounds like the name of a comedy duo.
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