George S. Ledyard

Most people can't stop their tip with precision and without bouncing because they are too tense (Iwama style not withstanding). Relax your arms. It is the left arm extension which stops the tip from dropping. If you extend your left arm out towards what you are cutting you can't rest your weight on the end of the handle and you can't control your tip. Your left arm at the end of a vertical cut should extend down towards a spot on the floor that is about 40 inches out from your center axis. If your left hand doesn't rise, your tip won't fall.

Also, it is important to keep both arms extended equally in a relaxed fashion. Many folks cut by pushing with their right hand. The power hand is the left hand. the right hand guides the blade towards the target. Equal, relaxed, extension will produce the kind of control you want.

The other factor which most people igore is the legs. If you are going to stop a full power cut within a fraction of an inch, the residual energy of the sword that wasn't used in the cut itself has to go somewhere. If your legs ar stiff, you will have to tighten your muscles to stop the cut and the tension will a) slow you down and b) make it difficult to stop your tip precisely. Keep your legs as soft as if you were doing an "egg toss".

Good exercise:
A partner stands in front of you with a bokken held in a lowered position. You stand just out of contact range and do continuous left and right kesa giris (yokomen cuts).

At random intervals the partner will suddenly raise the sword up vertically in fron of him and you are expected to stop the cut and do so with your sword kust touching the partner's bokken. This teaches you how to cut with commitment but stop the blade at any instant as required. (most Aikido folks don't really cut with commitment when they do sword).