A steady hand and a sharp knife are all you need to cut corn kernels off the cob. A chef’s knife is fine if you’re comfortable with it, but a smaller knife works well, too.
Cut the ear of corn in half crosswise. This gives you a flat surface on which to stand the pieces and reduces the length of the cob so the kernels don’t have as far to fall and won’t bounce as much.
Stand a piece of corn on a cut end and slice down the length of the ear between the kernels and cob. Try to get as much of the kernel as you can, but don’t cut too close to the cob or you’ll have tough bits on the kernels. Rotate the cob and repeat until all the kernels are cut.