Gohon Kumite and Sanbon Kumite are almost identical except since it is shorter it forces you to catch on to your opponent more quickly. Due to this, I just repeat the points of Gohon Kumite:
Sanbon Kumite at first seems rather monotone since we attack and block with the most basic techniques. However, the reason behind this training form is to learn powerful and accurate attacking and blocking. Both parties know the techniques and can focus on the proper execution of their part. It is important to learn at this stage:
The proper target level (Jodan, Chudan, Gedan)
The proper target area (Nose, Solar Plexus, Groin etc.)
The proper body posture
The proper spirit (Tokon Fighting Spirit)
The proper stepping in Zenkutsu Dachi (attacker steps inside of the opponent’s stance or toe to toe)
(It is important that the attacker does 5 separate attacks rather than running the techniques together. Start 5 times with full speed - with full “new” focus, commitment and aggression!!!)
The proper block (Ake Uke, Soto Uke, Ushi Uke, Gedan Barai, etc.)
The proper timing of your block
The proper target area of your block
The proper stepping backwards
The proper spirit (calm mind while getting attacked)
(It is important that the defender learns how to read the attacker’s movements, distance, reach and timing of execution of his techniques.)
Beginners especially should watch their upper body posture to ensure the spine and the head stay straight. Don’t hold your breath either. These points are especially important to watch during the counter attack. Often the defender has moved too far back and now tries to adjust the distance for his counter attack by leaning his upper body forward rather than adjusting the missing distance by foot/leg work.
Note from the author: More advanced Karateka should try to shorten the timing between last block and counter. One also can play with the timing so that the techniques are not all done in the same rhythm.