When a Win Isn't a Technique
A wrestler drives his opponent to the edge, has the bout won — and steps out himself, half a second too early. Nobody did anything to him. Sumo has a name for that, and it is not a technique.
As the article on kimarite sets out, every bout gets a name describing how it was won. But some bouts are not won by anybody. They are lost.
Sumo keeps a separate category for these: 非技 (hiwaza) — "not a technique". The word says exactly what it means. The winner did not do a thing that has a name; the loser defeated himself.
Isamiashi — the excess of zeal
The one you will meet most is 勇み足 (isamiashi). The characters mean something like "brave foot", and the usual English rendering is "excess of zeal".
It happens like this. A wrestler is driving his opponent backwards toward the straw. The opponent is going out — the bout is effectively over. And in the last instant, the attacker's own momentum carries his foot over the line first.
He was winning. He lost.
Why the sport bothers to distinguish this
It would be simpler to record the win under whatever the other man happened to be doing. Sumo does not, and the reason is worth noticing.
The kimarite is a record of how a bout was won. If the winner did not do anything, saying that he did would be false. So the sport keeps a category that says, in effect: nothing was done here, and the result stands anyway.
That is a quietly honest piece of design. The win counts exactly the same — but the record does not pretend.
This sits next to the rule described in how a match is won: a wrestler who is already past saving is in a state called 死に体 (shinitai), and if his opponent is in that state the attacker can touch down first and still be given the win. Both ideas exist because sumo cares about who was already beaten, not only about who touched the ground first.
Why it is not embarrassing
To a new viewer, losing this way looks like a blunder. Watch a few and the impression changes.
An isamiashi is what happens to a wrestler who committed completely to finishing the bout. The alternative — holding something back at the edge, in case he needs to stop — is how you fail to push a man out at all. The mistake is made of the same material as the win.
The trap for new viewers
If a bout ends and the crowd reacts strangely — a noise that is neither cheering nor disappointment — check the feet in the replay. You have probably just watched a bout won by the man who was losing it, and the announcement will name no technique at all.
What to watch for
At the edge of the ring, stop watching the man going backwards and watch the man going forwards.
Specifically, watch his back foot. In a normal push-out it stays inside; in an isamiashi it crosses the straw a fraction before his opponent's does. That fraction is the whole result, and it is why the sand outside the bales is swept smooth between bouts.
The list this category sits outside of, and why the sport names results at all.