It might be obvious, but I can't figure out what the hell they mean at the first riddle with the chests... help?

EDIT: Same with the second one(red room). What unique skill exactly?

The location of the chest in the first room is represented in form of the city. The one that should be open is the chest that represent the bar and arena. As for the second room, I assume it depends on which girls route you are on, then that girl skill should be the one to defeat the enemy.

For the first test, the chests are in the form of the town map. So you have to...

For the second test..

Thanks! Yeah, thought it was that, but didn't figure out the exact locations and was getting frustrated trying it two-by-two.