Hiraken uchi

Hiraken uchi contacts targets with the front of the second knuckles, circled in red.

Hiraken uchi (literally: "leopard-fist strike"), is a more robust variation of the four-fingered spearhand strike. Hiraken uchi is thrown just like a front-foot or reverse punch, but impact is made with the second knuckles instead of the seiken. Hiraken uchi is used to attack soft tissues, such as the opponent's throat, solar plexus, abdomen, bladder, or armpits.

[video of a hiraken from the front and the side]

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