といえども・とはいえ: the difference
といえどもN1
Meaning
Even
Past papers
Example
ヒジカタが恐るべしと雖も、スギモトの敵ではない。
Formidable as Hijikata may be, he is no match for Sugimoto.
とはいえN1
Meaning
Though, Although
Past papers
Tested 5 times in past papers
Example
馬は肉を食べることができる。とは言え、普通は食べない。
Horses can eat meat. That said, they usually don't.
How to tell them apart
「といえども」 is the most formal and stresses 'no exception, however special'.
「とはいえ」 is a common modern 'that said, ...' turn.
「といっても」 is more casual: 'it is A, but not as much as you think': 「春といっても、まだ寒い」 (It's spring, but still cold).