Torah Temimah cites Bava Kamma.
“And he denied it” — might one think that if he said “you found two oxen of mine” and the other replies “I found only one,” he is liable? Scripture says “and he denied it,” excluding this case, for he did not fully deny.
Miyut of incomplete contradiction — partial admission of one of two is excluded.
Where the claimant cannot force a definitive “you must have both,” partial admission is not “kichhesh.” The asham structure requires a complete denial of the claim.