Die Schwalbe, 1998 -- Invalid position?

[mjk]

Nr. 10218 [3Brq2/P1ppRp1K/4p2p/6p1/6NP/3P1P1k/1PP1bPrb/3BnQnR]

Isn't this an invalid position?

2 Black Pawns have been captured -- one Bl. P was captured on f3. How did that Bl. P get there? Only 2 White figures have been captured, but the Bl. b-file P needs 4 captures to get to the f-file. (The a-file P can't get there at all, of course.)

ex falso quod libit

[mjk]

What about a Black Pawn promoting, and the new piece then moving to f3 to be captured?

That is consistent with the position.

So I retract my contention that the problem is invalid.

Sorry.