Today's puzzle is a special three-parter. You are asked to provide:
(a) white's first moveMuch kudos and cake to the reader who can provide us with three satisfactory answers. All will be explained soon . . .
(b) proof that this is the only key move possible (that's to say, proof that the puzzle isn't cooked)
(c) the relevance (a) has to the Streatham and Brixton Chess Blog today.