A knight positioned in the corner of the board can make two moves while a knight positioned on a central square can visit eight possible squares. (Side question: Given a number between 2 and 8, is it possible for a knight to have that number of possible moves? For example a knight on b1 can make 3 possible moves.) In the previous post we examined problems in which a pawn could make the maximum possible number of moves. In this post we will examine problems in which a knight can make its maximum eight moves. Such problems are often known as task problems. When a black knight makes its eight possible moves and the theme is called a knight wheel. When a white knight makes its eight possible moves it is called a knight tour. As usual you will scroll down for the solution to my problems and click on the diagrams for the solutions to the other problems.
For the first problem the key 1.Re4 makes 7 threats (2.Sb3/Sc2/Sc6/Se6/Sf5/Sf3/Se2). The key gives a flight and the king's move 1...Kc5 forces 2.Sf5. The move 1...c2 forces 2.Se2. Moreover, 1...Sxb5 defeats all of the threats but finishes the knight tour. Answer to the side question: A knight can have 2,3,4,6, or 8 moves.
A position in which every black move has a set white continuation is known as a complete block. To solve such a problem one just needs to find a white move that preserves all of these set white moves - a waiting move. Sometimes there is not waiting move to be found and one has to change one or more of the mates. If there is no threat after the key then such a problem is called a changed waiter or mutate. The Warton brothers specialized in changed waiters and their work is represented below. Since I love mutates (who doesn't) I have selected several problems. As usual we begin with one of my own.
A pawn in its game array position (not on the edge of the board) can make 4 possible moves: forward one square, forward two squares and, if the opportunity presents itself, it can capture on the adjacent diagonal squares. In a problem, when a black pawn makes its four possible moves the theme is called a Pickaninny. When a white pawn makes its four possible moves in the course of a problem the theme is called an Albino. We have seen examples of both themes already in the half-pin and AUW posts. As usual we begin with an unpublished problem of my own and then get into some of my favorite examples.
Solution to the first problem: notice that the wQ controls the squares d5 and d6. If these squares are blocked with the bPd7 then the wQ can use this to her advantage. In particular, notice the dual after 1...d5 2.Qf4/Qh2. The key 1.Kg6(-) clears the way for the wQ to handle 1...d6 with 2.Qg5 and gets rid of the dual.
Allumwandlung (AUW for short) is German for "complete promotion", that is, during the problem a pawn is promoted to a knight, bishop, rook, and queen. In a two mover one way to accomplish AUW is through a twinning or quadrupling as it would be.
Solution: The promotions go in turn: (a) 1.f8=S (b) 1.f8=B (c) 1.e8=R (d) 1.f8=Q. As mentioned above none of the keys take any flight squares from the king, in fact, they give flight squares in (a) and (b) by setting up indirect batteries and sacrificing the wS.
On the side I like to dabble in chess problem composition. I am mostly interested in two and three move direct mates. I hope to convey the beauty and logic of chess problems with this blog. In the entries are some of my favorite problems and my own problems. Before looking at the problems I suggest reading this introduction to the chess problem world by the British Chess Problem Society. Also, here is a list of terminology and themes. Here is a link to my problems on yacpdb.
1. "Choose wisely" The Problemist Supplement, Sept. 2016
2. "Double checking white in a two mover" StrateGems July 2016
3. "Double check without capture" The Problemist Supplement, January 2018
4. "The disappearing Nowotny: Part I" The Problemist Supplement, March 2018
5. "The disappearing Nowotny: Part II" The Problemist Supplement, May 2018
6. "The disappearing Nowotny: Part III" The Problemist Supplement, July 2018
7. "Castling with half-battery and Fleck themes" StrateGems, July 2018
8. "The Baku Nowotny" StrateGems, January 2019
9. "The Romanian Nowotny with Fleck" The Problemist, March 2019
10. "Mirror Image" The Problemist Supplement, May 2019
11. "White King in Check" Problemas, July 2019
12. "A Simple Mechanism", StrateGems, July 2019
13. "Miniatures with castling and (partial) Fleck" Problemist Supplement, September 2019
14. "Taking the Straitjacket off the Fleck" The Problemist Supplement, November 2019
15. "Unforced threats" The Problemist Supplement, May 2020
16. "Ojanen in Miniature" The Problemist Supplement, May 2020
17. "Developments in the Finnish Nowotny" The Problemist, July 2020