Grains
The part of rice that stands up tall in the air (at the end of the stalks) is the grains.
If you think about this one it'll make good sense. Just imagine rice stalks standing up into the air.
りゅう
つぶ
None
You have a box of grains. Ryuu (りゅう) from Street Fighter is doing training by punching the grains to strengthen his fingers.
He has his hands flat, and stabs his hands into the grains. Yah! Yah! Yah!