Thanks for @Sadaharu introducing the Igosil app to us, and I have been grinding it’s Joseki card battle for over a month. I finally reach the #1 spot today.
This is the final board when I beat the previous #1
After a month of constantly farming joseki cards by deliberately resign to keep my Setup battle ranks below 10k to gain more joseki cards each round (beating 13k to 15k bots by a large margin yields 4 cards each), I found that Joseki Card battle is not like normal Go, but I have to think like a 10k bots to disrupt the opponent’s defense plan, and the elemental counter matters but not the most important if I can at least be neutral in the elemental balance. Not sure if they really matter, but flying element for outside influences is very important for the offensive, especially as ladder breakers.