Yen is a tech card against MS. It's primarily for Dagon Swarm, more specifically Woodlands. It can work as a backup for GH vs Consume as well if they don't pull it from Marching Orders. It's not ideal in some cases for sure but can still get value vs other decks if played at the right time.
I hit R20 running a Witcher/Smuggler build and swapped to one of the decks built by Purple (good player, hitting up his stream can help). Ran that to around 4350. Ended up tanking to 4.1k shortly after because people figured out how to put the deck in tough spots and a string of horrible draws/mulligans. From there I made some changes and started going back up. It seems the biggest thing is to learn from misplays and quickly adapt your build to the decks you're seeing. Oddly, it feels harder to get a read on the meta at lower MMR because people do weird shit
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