*°_°*

There are several ways of solving this one. I played my better times unlocking that red king at the very end of the game. It might cost some moves, though.

You are right Alinka. Unlocking the red king in the right pile is crucial. In order to do that we need 8 (where we shall put 7). In order to find 8 use the first empty space with the *other* red king. This will allow to free up 8...

to unlock that red King, use the red king from the stock before second black king, then move on it Q and J

6, 9
unlock the red king in the right pile AAP