Endgame Bootcamp 3

Black to move and draw

Because this one is already in Lichess Tablebase territory, you are able to experiment with how/why there's possibilities to draw and win for both sides as you deviate from the starting position. 8/5r2/R5k1/6p1/8/7P/6PK/8 b - - 3 42
What happens when Black plays Kh5 or Rf6? White Wins!
Kh5 g4 Kh4 Rh6
Rf6 and White must take back immediately, or be in drawn territory. After Rxf6 Kxf6 only one move maintains the Win for White.

Kg3! This is because the White King will be able to keep the Black King away from their pawns.
The g4 square is not available for Black, especially after Kf5, h5 gxg5 Kxh5.If Kg6 instead of Kf5, h4 is now drawn because of Kh5. White can play any other move and be winning.

Final Thoughts

Black must wait for the right times to offer a Rook trade on the 6th rank.
In lines like Kf5 Kg1 Rf6 Rf6 Kf6 Kf2 Kg6 Kg3 Kh5 Kf2 Kh4 Kf3 Kh5, Rook trade is bad.
However Kf5 h4 gh4 g3 hg3 Kg3 Rf6 to offer the ultimate liquidation.
Kf5 g3 Rf6 is still drawn because the White King is not able to step to g3 until a pawn is moved.
Example: g4 Ke5 Ke3 Kf6 h4 gh4 Kh4 Kg6

A Pure Pawn Ending

For good practice in calculation, think about Black's route to promotion before moving any pieces.
I saw as far into the future as....Kd4 Kf6 Kc3 Ke6 Kb2 Kd5 Ka2 Kc5
I incorrectly thought Kb3 was best, but this allows drawing chances if Black doesn't follow through accurately.

If Kb3 Kb5 then a4 is drawn
The cleanest win for Black after Kc5 is a4!

Don't allow another draw after Kb4, by playing a3! Just take on b3 with the pawn and keep pushing. White's threat to promote is non-existent.

Look deep Josh. It's there, it's 12 moves away but it's there and you've got him.....Don't move until you see it."