Guidelines for Partner training in Karate
In all Karate partner training exercises when attack/block exercises are performed, the rule is: The person attacking moves at the command of the instructor. The person blocking only moves once the attack has been initiated.In partner training such as Ippon Kumite (one-step sparring), typically the person assigned to be attacker, stands in a traditional ready position (Chudan No Kamae, middle level fighting posture) or a natural fighting stance (Shizen dachi no kamae). The person blocking usually assumes a formal attention stance (this varies from style to style).
Guidelines for the person attacking
If it is a new Karate technique that either your or your partner are not familiar with, perform the first few repetitions at slow pace, until you’re certain that your partner can properly block your attack without the risk of injury. If your partner is comfortable with blocking your attack, increase the speed and power of your attack as if you “mean it”. There is no point in teaching your partner how to block “sissy attacks”.Sometimes the person defending already positions himself in the way they’re going to move when they block. As the attacker, do not co-operate here. If you’re meant to aim for the solar plexus, then aim there. You fix your target at the moment you’re given the command to attack. Do not follow a moving target once you have initiated the attack (because you’re not supposed to know where you partner is going to end up). However, if the person defending has changed the distance between individual repetitions of the exercise, adjust your distance quickly before you attack, instead of overextending your limbs and thus performing an unrealistic attack.
What NOT to do
Do not hit with full speed and power from the word go, rushing in like a bull. Do not continuously hit slow and without commitment, as your strike becomes effectively unblockable because your partner has nothing to block.Guidelines for the person defending
Move only once your attacker moves. In other words, don’t start your defensive action until an attack has commenced. When your opponent attacks, block the attack, whether there was a command from the instructor or not. Block every time as if it was a serious attack, regardless of the intensity of the attack - take it seriously every time. Don’t adjust your stance or technique because of the short-comings of your partner who performs the attack.This is a common problem for new Karate students. They hear the instructor, and they start their blocking technique, regardless of what their attacker is up to. Clearly, a block performed this way is not very effective. If the blocker does his block to the count, the attacker who may have delayed his attack is now pretty much at a loss of what do do. He can either contort himself to put his punch where it would have been if it had been properly blocked (bad idea). He can simply ignore the defenders premature movement and continue on with the attack undeterred (and thus whack his partner in the nose - very bad idea). He could be tempted to ask the defender to reset his position so the exercise can be properly performed (bad idea too - this will make both partner lose sync with the instructor).
Not following these simple guidelines means that you always move in preconceived ways, practicing a useless choreographed ballet which has really nothing to do with Karate or martial arts. 
