Spot the Back Rank Weakness

Even though (if you're at all like me) we still fall prey to "simple" back-rank weakness tactics, I think these tactics are sometimes dismissed as obvious, beginner cheapos. However, these motifs can be quite deeply concealed. The following example from Marshall-Alekhine, NY 1924 caught my attention:



20...h6. Alekhine: "It was surely disagreeable to deprive the Rook of the control of h6, and yet there appeared to be no other way of preparing for Rf6 (20... Rf6 21. Qxe4 Qxe4 22. Nxe4 Rxe4:



23. Rxd5." Of course 23...cxd5?? 24. Rc8+ and back-rank mate to follow. It's not hard to calculate this forcing line, but you'd have to look pretty carefully at the first diagram to see that there was a potential back-rank weakness and that making luft with ...h6 was a good idea. Besides being a good example of calculating a forcing variation, this is also a good example of playing "real chess" a la Heisman: "What can my opponent do after I make the move I want to make?"

To add a dose of humility, I'll conclude with a recent blunder of mine from a blitz game:


I had actually made luft with ...g6 seven moves ago, to hopefully thwart back-rank problems. In time trouble I played 29...Rcc7??, hoping for something like 30.Bxc5?? Rxc5 31.Rxc5 a2 -+.

However, to my opponent's credit, he almost immediately whipped out 30.Bh6! Ke8 31.Ra8+ 1-0.

Was Alekhine Unaware of the Noah's Ark Trap?

The Noah's Ark trap refers to the following tactic that can be found in lines of the Spanish. After, for example, 1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 d6 5. d4 b5 6. Bb3 Nxd4 7. Nxd4 exd4 8. Qxd4?



8... c5! 9. Qd5 Be6 10. Qc6+ Bd7 11. Qd5 c4 -+ traps the bishop.

Yet, in a footnote to Yates-Alekhine, NY 1924, Alekhine says {note: I'm converting the notation to algebraic} "...White, after 5.d4, must reckon with either choosing an immediate drawing line (5...b5 6.Bb3 Nxd4 7.Nxd4 exd4 8.Qxd4 c5 9.Qd5 Be6 10.Qc6+ Bd7 11.Qd5 Be6 = {instead of 11...c4!-GP}), or being forced to embark upon a doubtful sacrificial variation beginning with 8.c3".

My understanding was that the Noah's Ark Trap gets its name from its antiquity. Yet I see that even 6 years after Yates-Alekhine was played, Steiner used this line as White against Capablanca (unsuccessfully).

Were the masters at the time of the NY 1924 tournament actually unaware of this trap, or am I missing something?