The pre-chop technique refers to mechanically breaking the nucleus into smaller pieces prior to inserting the phaco probe into the eye. There are specialized instruments like the Akahoshi Pre-Chopper and guest surgeons here on Cataract Coach have presented multiple other options. This video shows a resident who is performing case #80 and I assist him by pre-chopping the nucleus into smaller pieces prior to inserting the phaco probe. This is accomplished by using just a 27g blunt cannula and a standard Nagahara Chopper. This makes the remainder of the surgery much easier and the case goes beautifully. You should learn this technique since it is useful, simple, and requires no additional instruments.
click to learn this simplified pre-chop technique: