<p>In the movie, from what I read, Boruto was supposedly going for a Gentle Fist finisher when Shikadai countered. I like to think that as per Hyuuga tradition, Hinata may have been teaching her kids Gentle Fist moves that don't require the Byakugan. She may even have told them about the Tenketsu. With the Byakugan unlocked, and able to see them, Himawari would have targeted them.
</p><p>The only thing I don't get is how it is possible for One Hit to forcefully close ALL the Tenketsu. Whatever the move was, it is much more deadly than the legendary 64 Palms.
</p><p>This explains almost all the things in the chapter. Hinata was surprised because she didn't know Himawari could awaken Byakugan, because naruto's Tenketsu were closed. Hima and Boruto are both trained in Gentle Fist.
</p><p>In the chapters that follow, Naruto, Boruto and Hinata all would know about Himawari's ability, though it's probably kept secret to protect her.
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