Try: 1.Rd3? but 1…Rf7 Key: 1.Rb6! (thr. 2.Bb3 and 3.Bd1#, if 2...Rf7 3.exf7 axb6 4.Bd1#) Re8/Rxe6 2.Bb3 (thr. Bd1#) Rf8/Rf6 3.Bd1+ Rf3 4.Sd3 (thr. Sf4) exd3 5.Bxf3# 4…axb6 5.Sf4#
Sacrificial key against a Siegfriedsturm/rook which attempts to sacrifice or position itself for stalemate, and white's strategy is to frustrate that in a number of ways by delaying its sacrifice, or in one variation, not capturing it at all, but pinning it against its own king, a form of shielding that should provide the desired stalemate, but is too late.
There is a logical attempt in addition to the try: 1.Rb7? won't work as the black rook need not worry about being captured and will just relocate within the rank to carry on its own plan of forcing stalemate. Note also that in the actual play if black plays 1…Rf7 (the refutation to the thematic try) then 2.exf7! zz axb6 3.Bb3 b5 4.Bd1#.
The apparently similar sacrifice 1.Rd3? fails, as when black captures on d3 then Bb3? stalemates black. White's initial rook sacrifice must provide at least two tempi for black!
