It says that the senior player ``performs'' the Nigiri. What does perform mean: is he the one with the white or the black stones?
unkx80: If I am not wrong, the White stones are usually placed at the senior player's side, and the senior player is the one who grabs the stones for the junior player to guess.
Chris Hayashida: An easy way for me to remember is that (o)nigiri (Japanese for rice ball) should be white. I'm really bad at guessing ages, so if I have the white stones next to me, I grab a handful and let the other player choose. More often then not, if you hand the other player the white stones, they end up playing white no-komi. If you're at a foreign Go club, they'll usually set up a game and tell you what to play. It's part of what you pay the entry fee for.
Imagist: At the Korean club I go to, people I don't know always assume that I am taking black (regardless of our relative strengths). Maybe they assume that because I'm an American I'm weak or something. Most of them are stronger than me, so I can't complain. But the point I'm trying to make is that if you aren't sure what to do, just grab the black stones. That way if you make a mistake you're being too respectful.