no. 584

White to play. Aronian–Carlsen, December 2019.
Carlsen won the third-place playoff, but Aronian found a nice finish in this game. What move prompted Carlsen’s resignation?
We regret that owing to print deadlines this is not a prize competition.
 
Last week’s solution  1…Qa7!! wins, as 2 Bxa7 Rxg2+ 3 Kh1 Rxh2+ 4 Kg1 Rag2 is mate.
Last week’s winner Paul Bell, London N10