Instrumental unit founded in April 2005 by Hayato (piano) and Hiro (cajón).

The arrows in the duo's name name are intended to have people read the word “Piano” from left to right and “Cajon” from right to left, resulting in “→Pia-no-jaC←”, meaning the piano and the cajon jacking a concert.

Many of their albums were released with alternate cover art or bonus discs as Village/Vanguard exclusives.