1. ... Rg7? 2.Kxg7 and one move late for H#6

Keywords: phoenix, excelsior, minimal, model mate, sacrifice key, sacrifice of black pieces (active), passive sacrifice, annihilation, square vacation selfblock, promotion, underpromotion, line opening

This problem was first published here on 2022-11-01, accidentally deleted by the system and reentered on 2022-11-08.