Which is correct: "blagodarya chemu" or "blagodarya chego"?

Actually, both options aren't quite correct - "blagodarya" requires the dative case, so the correct form is "blagodarya chemú" 😊 The second option with the genitive case isn't used in standard Russian.

Actually, the question isn't quite framed correctly, because this isn't a choice between two equally valid options. "Blagodarya" is a preposition that always requires the dative case, so only "blagodarya chemú" is correct. Using the genitive case is simply a mistake, not an alternative.

I remember how teachers in school would literally explain it on their fingers: the preposition "blagodarya" goes with the dative case, just like "k", "po", and "vopreki". I even came up with a test phrase - you substitute a pronoun and it becomes immediately clear: "blagodarya emu" (dative case), not "blagodarya ego" (genitive). If instead of "chemu" you want to substitute a noun - it's the same thing, you just decline it in the dative: "blagodarya usiliyam", "blagodarya pomoschi", "blagodarya udache". There's simply no such thing as "blagodarya chego" or "blagodarya pomoschi".

The confusion also comes up because there are similar prepositions like "vmesto" that require the genitive case. In that case, yes, "vmesto chego" would be correct. But "blagodarya" is a completely different situation.

Yes, "blagodarya chemu" is the only correct form, because the preposition requires the dative case 😊 The tricky part: the stress falls on the last syllable in "chemú", not on the first one like some people mistakenly pronounce it.