Success Through Miscalculation

Working through the Anthology of Chess Combinations after eight months away, I started badly. I kept missing simple forks and other elementary tactics. By the time I added a second pour to my coffee cup, however, I was beginning to solve some problems.

I found the full combination from Kagan -- Burnevsky 1964 (ACC 280) without error.

Black to move

In the next problem, I quickly identified White's queen as the target and played the correct move.

Black to move

From Stepanov -- Romanovsky 1926.

However, my calculation included an impossible skewer and I missed the second move of the combination. The Chess Informant Solver's Kit asked only for the first move, so I was credited with success. You and I know, however, that it should count as a fail.