Nobuo Sato has long been one of the leading Japanese Coaches and it comes as little surprise that Mao Asada would choose him as her new coach.
Asada has been looking for a new coach since splitting up with Tatiana Tarasova. Tarasova was heavily criticized for 'weighing down' Asada's skating last season with an over dramatic and heavy free program.
Nobuo currently coaches, among others, Takahiko Kozuka. At one point or another, he's coached a good portion of the top Japanese competitors.
I think Mao will flourish under Nobuo's tuteledge.