The chef's knife, typically eight inches long with a curved belly, is built for the rocking motion. The heel stays on the board while the tip traces an arc, moving through vegetables with a continuous forward-and-backward rhythm. This shape suits cooks who work by feel and speed, especially when processing large volumes of onions, peppers, or carrots. The blade's curve means less downward force is needed; leverage does much of the work.
A nakiri, usually seven inches with a tall, flat rectangular blade, takes the opposite approach. It cuts almost entirely with a downward chop or slice, the wide face pinning vegetables against the board. The flat edge and substantial weight concentrate force straight down, making it excel at clean, perpendicular cuts through firm vegetables. The broad side also shields fingers from the blade and can scoop chopped pieces into a pot.
The santoku, a Japanese answer to the chef's knife, splits the difference. It has a slight curve but less pronounced than a chef's knife, and the blade tapers to a thinner edge. The cutting motion is primarily downward with minimal forward-backward action, making it a precision tool for vegetables that reward delicate, controlled cuts like tomatoes, herbs, or vegetables meant for presentation.