At the King's Clash two weeks ago, the solution to all six problems was the move of a king. One entry had six correct answers. The young player won a book.
The knight's move may not be the first in the winning combination. It is often the last.
The first two are from Gioachino Greco, c.1623. Number three is based on one in several problem books. Number four come from a game won by Lionel Kieseritzky in 1842. The fifth, from Horwitz--Bledow (1837), contains a common idea that can arise in the opening. Problem number six is from the 21st match game between Louis-Charles de la Bourdonnais and Alexander McDonnell (1834).
Black moves first