premise: There are two men engaged in a karate match, the man on the left kicks the man on the right in the face while the man on the right kicks the man on the left in the groin. hypothesis: Two men kick one another while performing karate.
entailment: If the men are in a karate match this indicates they are 'performing karate', also 'Two men kick one another' is a much simpler rephrasing of 'the man on the left kicks the man on the right...the man on the right kicks the man on the left..'.