Nukite is the strike with the tips of extended fingers. At times it traditionally calls “spear hand” strikes. Those strikes are targeted vulnerable soft body points – primarily neck and throat as well as abdomen aria.
It is many forms of the spear hand. In his book “Essential Karate” Mas Oyama (the link is to scribd.com page that contains Mas Oyama book; I don't know it's copyright status; this link is to Amazon.com) showing half dozen different versions targeted varicose body points. However, in the real combat it is no time to make a choice between multiple options. In spear hand the striking fingers should be very sturdy. As I’m not training nukite as it trained in Kyokushin karate, I need a form that present less risk of injuries to my fingers and wrist. Striking with one or two fingers is too risk prone. As Aikido experience recommends finger lock techniques to be used on two fingers as one is too breakable and three is too sturdy, I’m using four-finger striking zone with my fingers slightly bend inward.
[This image is from Wikipedia Commons, German edition; Image is licensed under Creative Commons;
link to the original image]
This “spear” hand position is sturdy enough to present minimal-to-no injury risk even for people who depend on the health of their hands, while – as well placed atemi – can inflict significant pain on enemy and became “fight enders”.
Atemi and use of nukite