Since we got started on the topic of whole-board endgame problems with Sunday Problem #20, here is another one.
This problem is from another Japanese problem book with an untranslatable name: 勝つヨセの絶妙な手順 (Katsu-yose no zetsumyō na tejun) by Mitsunaga Junzō 6p. A rough English translation would be Exquisite game-winning move orders in the endgame – feel free to suggest a better one in the comments if you can think of one!
No komi or captures, Black to play. What is the best outcome for both players?