The term Waza-ari (技あり) actually means that a valid technique has been performed but it does not quite warrant an Ippon. It does not literally mean ‘half a point’. Assigning the meaning ‘half point’ to it comes from its mathematical value in the sense that obtaining two Waza-ari equals an Ippon, which is a ‘full point’. So, in most martial competition i.e. karate, kendo, judo, and jujitsu, it is understood as a half an Ippon.
As this is strictly a Shotokan document we will focus mainly on Waza-ari as it applies to Shobu Ippon or Shobu Sanbon Kumite.
A Waza-ari score in Shobu Ippon and Shobu Sanbon has to meet most of the criteria that an Ippon (see Ippon for score criteria) score is required to meet but receives only half an Ippon.
Within the WKF sport karate (the official Olympic competition karate) point scoring competition, however, it takes a different role. In an 8 points to a win bout, where Ippon (see Ippon for WKF Ippon score criteria) is worth 3 points, it is worth 2 points and, another, lesser score, Yuko, is worth 1 point. In that competition a Waza-ari can only be awarded for a chudan geri.