I'm somewhat stuck as well on this. Not sure where to go after winning the second battle.
BTW I think its not cheating or purely luck. Think about 2 moves ahead at least in the first few battles.
If you win paper against rock, she will often throw paper next, It seems like the logic of "scisors should beat paper so The player thinks I will throw scisors next and he will throw rock to beat me. If I throw paper I will beat his rock.
The good thing about your theory is that it's really easy to test.
I made a save right outside the cave (since I no longer have one of the fight with Rena or the prologue ones with the other girl) and tested on the slime. Now with your theory, it's impossible to do for the very first move as there's no logical way to tell what their first move will be. Well the first test I ran was 10 battles, 3 moves each and the second was 3 battles until victory/defeat.
First test:
In every single battle, he won the first 3 moves. Now with your theory, it's very possible that he just anticipated what I would throw...but here's the kicker...as I said before that's impossible for the first move. It should be, by all logic, pure luck.
10 battles, each time me randomly picking R, S, or P, and he just happen to choose the one that works against me. 0 wins for me, 0 ties. That's next to impossible with a 1/3 chance. This is like losing a coin flip 30 times in a row. Possible? Yes. Likely? No.
Second test:
3 battles, 0 wins 3 losses, 1 round won and hit, 1 round won and he dodge, 0 ties.
Oh and I'll add that not a single one of those 2 rounds won was the first round. This is not possible unless it's input reading.
