There are five Heian forms, containing a great variety of techniques and almost all of the basic stances. Having mastered these five forms, one can be confident that he is able to defend himself competently in most situations. The meaning of the name is to be taken in this context.
Heian Sandan has a heavy emphasis on simultaneous attacking and defending. Example. Scissor blocks at the start, and the elbow parry into a back fist in the last half. This is also the first kata we see the crescent kick implemented.
"Heian Sandan incorporates a range of varied techniques, beginning with an inside to outside block, followed immediately by a simultaneous inside-to-outside block/downward block combination. The kata includes a response to a situation in which the wrist has been grabbed upon delivering a spear-hand strike, which involves the twisting and rotating of the body followed by an attach. The final sequence of Heian Sandan assumes that an opponent has seized from behind, calling for a back elbow strike performed simultaneously with an over-the-shoulder vertical punch to the opponent's face."