Nikkan Sports is carrying an article about Ryosuke Kikuchi asking fans not to do the wave because it makes the ball difficult to see.
I know everyone is excited, but please do not do the wave while the ball is in play. It makes the ball harder to see…
Incidentally, the Hiroshima Carp website includes the following note about waves during pro yakyu games at Mazda Stadium:
Please do not take the lead in “wave” (wave-like) cheering or wave cheering.
Source: Nikkan Sports 9/6/2016