1.
even if one concedes the point, even granting that
An expression used to reluctantly grant a point or make a major concession in an argument, before stating that even so, something remains unacceptable. Literally 'yielding a hundred steps,' implying maximum concession.
Usage
Used to make a rhetorical concession before presenting a stronger counterpoint. The pattern is typically 百歩譲って～としても (even granting that ~). The speaker does not actually agree with the conceded point — the concession is hypothetical, used to strengthen the following argument.
Etymology
From the Chinese idiom meaning to yield a hundred paces, representing the greatest possible concession.