How to use retrograde analysis to perfect your chess skills

This chess tutorial from Grandmaster Alexandra Kosteniuk is a perfect example of Retrograde Analysis.

Wikipedia defines Retrograde Analysis as a technique employed by chess problem solvers to determine which moves were played leading up to a given position. While this technique is rarely needed for solving ordinary chess problems, there is a whole sub-genre of chess problems in which it is an important part; such problems are known as retros.

Retros may ask, for example, for a mate in two, but the main puzzle (at least in modern retros) is in explaining the history of the position. This may be important to determine, for example, if castling is disallowed or an en passant pawn capture is possible. Other problems may ask specific questions relating to the history of the position such as "is the bishop on C1 promoted?". This is essentially a matter of logical reasoning, with high appeal for puzzle enthusiasts.

This is not a standard chess problem; on which square was the White Queen captured?

LEVEL: Difficult
CATEGORY: Retro