Ozeki Kotoshogiku rinses his mouth with power water. Toyonoshima is the Kachi-nokori.
Chikara-mizu (力水) is a ladleful of water with which a wrestler will ceremonially rinse out his mouth prior to a bout. It must be handed to him by a wrestler not tainted with a loss on that day, so it is either handed to him by the victorious wrestler of the previous bout if he was on the same side of the dohyo, or if that wrestler was defeated, by the wrestler who will fight in the bout following. This system works well until the last match of the day (musubi no ichiban, 結びの一番) when one side will not have someone to give them the power water. This is due to the fact that one of the sides from the previous match lost and there is no next match, so there is neither a winner from the previous match, nor a next wrestler to give them the water. In this case a winner from two or three prior matches will be the one to give them the power water. This wrestler is known as the kachi-nokori (勝ち残り), which means the winner who remains.
Kachi-nokori (勝ち残り) literally translates as the winner who remains. During a day of sumo the power water is only given to the next wrestler by either a previous winner on their side of the ring or the next wrestler to fight on their side of the ring so as not to receive the water from either the opposite side or from a loser, which would be bad luck. However at the end of the day, one side will not have a winner or a next wrestler to give them the water. In this case the wrestler who was the last to win from their side will remain at the ringside in order to give them the power water. This individual is known as the kachi-nokori.
In 2020, due to the COVID-19 outbreak, wrestlers are still suppose to perform the same motion, but they can't rinse their mouth with the water. This was reverted back on day 1 of the November 2023 tournament, after almost 4 years since the suspension of the rinsing.