Not a knockoff, but a real Okinawa supermaket chain サンエー (San-A) mentioned in the credits of "Okitsura: Fell in Love with an Okinawan Girl, but I Just Wish I Knew What She's Saying".
https://ja.wikipedia.org/wiki/%E3%82%B5%E3%83%B3%E3%82%A8%E3%83%BC_(%E6%B2%96%E7%B8%84%E7%9C%8C)