In the scenes of fight in old stories, I sometimes encountered a phrase ~やまさりけん usually in the compound form:
力やまさりけん
腕やまさりけん
What is the exact meaning of the phrase and what part of the sentence is it?
太郎の力やまさりけん突き出した槍は相手の体に突っ込んできた。
At first I assumed it was 勝り{まさり}剣, but in the above example it was used in a spear fighting scene and it does not seem to work grammatically. It seems neither an adverb nor an adjective.
Also, shouldn't comma be used after まさりけん in the above example?