Previously, on tastingmenu.wordpress.com –
I was recently asked about wetting the hands for making nigiri. matsuhisa-sama mentions the water to vinegar ratio is 3:1 (Nobu West, p 196) . He admonishes that more than a light coating on the hands will prevent the shari from properly sticking together. Interestingly, Shizuo Tsuji (Japanese Cooking: A Simple Art, p. 292) says the water to vinegar is 9:1.
As a side note, Iron Chef Morimoto comments on wasabi between shari and fish: …to the type of fish you’re eating…more fat, more wasabi… http://www.foodandwine.com/how/morimoto-sushi-three-golden-rules . This apparently echoes/confirms Matuhisa-sama’s comment about knowing the amount of wasabi to use with different fish.