What is the glyph origin of 克?
Dislcaimer: The interpretations of the glyph forms and OC reconstructions are my personal opinion. Professional opinions state that this character is still open for interpretation.

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I guess you can view「克」(Baxter-Sagart OC: /*kʰˤək/, to achieve victory over/subdue/defeat an opponent in a military confrontation), as being a merger between semantic「由」(battle helmet, now written as「冑」) and reduced phonetic「革」(/*kˤrək/). The graphically reduced「革」looks like「⿱廿尸」or「⿱口尸」(picture of animal skin and horns).


  Specifically, the bottom part of「由」is merged with the top part of the reduced「革」.


For reference:


「由」

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「皮」(skinning an animal)

西周金九年衛鼎集成2831秦簡秦律十八7睡虎地秦簡西漢隸孫臏・220銀雀山漢簡今楷　
「革」(picture of flattened animal skin). Roughly speaking,「⿱廿尸」or「⿱口尸」is「革」folded in half along the animal's spine.

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