Good: right and left symmetric; beautiful curve line; fan shape from the front; sides solid; slightly slender from above; shari not overflowing the neta.
Bad: neta centre misaligned; skewed; straight line (no curve); too roundish; height too low; loose on the sides; uneven; too long; push from top and bottom not enough; shari overflowing.
“Koba” (the cut face) is face-up when you prepare the nigiri.
Forming (right-handed)
Rice in the edobitsu (cypress tub, wetted). It's a little above 35 °C; by serving it's ~35 °C.video 3-5
Tezu on three fingertips (rice page). Rice doesn't touch the palm.video 3-5
Right hand takes the rice; left hand takes the fish. Rice onto the back of the fish.video 3-5
Left thumb presses a shallow dimple in the centre of the rice; right index and thumb hold the tip and base so the rice doesn't stretch.video 3-5
Release the thumb, lay the right index on the rice; close the left palm a little so the fish sticks to the rice.video 3-5
Open and flip with index and middle finger, pushing rice and fish together toward the fingertips: fish now on top.video 3-5
Close the two “legs” of rice with middle finger and thumb; back into the pocket between palm and fingers.video 3-5
Fold the fingers to hold the sides, thumb under the fish aligning the far end, two right fingers cover the top to shape.video 3-5
Rotate clockwise with middle finger and thumb; same closure. Once more for the other side. Done.video 3-5
Edo style: incision on the right-hand side.
More wasabi on fatty tuna.
Many decorations possible on kohada; head top-left, slice shallowly.