The Yin and Yang seals.

[Ansatsuken]

And the other one to be remember is, in 4 DB, sometime we need to relaid on it, Hagoromo possesses complete set of both half, yin and yang, that mean he alone can create and carry this two seals as he shown us in the manga, but sure but I dont to sure whether Hamura having both half, or just a yin half, let just consider he most profficient on yin half as the proof he having doujutsu Byakugan, that mean the yin seal is suited and dominant for him.

 

[Torche]

And the other one to be remember is, in 4 DB, sometime we need to relaid on it, Hagoromo possesses complete set of both half, yin and yang, that mean he alone can create and carry this two seals as he shown us in the manga, but sure but I dont to sure whether Hamura having both half, or just a yin half, let just consider he most profficient on yin half as the proof he having doujutsu Byakugan, that mean the yin seal is suited and dominant for him.

It's kind of confusing. Both Hagoromo and Hamura are portrayed as "Yin" and "Yang": Hagoromo; Yang, Hamura; Yin. But, they are both Yin and Yang at the same time. I believe that it was confirmed that Hamura is the Kaguya descendant too. Which makes Byakuyan (Yin) and Shikotsumyaku (Yang). Hagoromo has Rinnegan (Yin) and a body power (Yang). They are both Yin and Yang, but are portrayed as separate "Yin" and "Yang". What makes it more confusing is that the Rinnegan and Hagoromo's Yin descendant (Sharingan) is superior to the Byakugan and the Shikotsumyaku is the "strongest" body which should make Hagoromo Yin and Hamura Yang going by the person who should have the strongest "Yin" and "Yang" affinities in a sense.

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I think that's all irrelevant though and am far too over thinking things. Hamura for whatever reason received the Yin seal.