No such thing.
The explanation doesn't compute. Never heard of what you are proposing.
White mates in 3
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Aug 23, 2011
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#3
The answer involves uderpromoting to a rook and Castling with the new rook on e8 (the King has not moved, the e8 rook technically has not moved and no piece is intercepting the King's journey, so "0-0-0-0-0-0" is a 'legal move' here
)
White mates in 3: