Text puzzles

First, let us dip into history. I’m going to show you a text puzzle I have used on countless chess enthusiasts over the years. A number of world champions – Karpov, Kasparov, Botvinnik, Spassky – were confronted, and all failed to solve it. Maybe you can do better?!

2025 Christmas Puzzle 6

Many will remember the classical problem we first told you about *in the past millennium! *Here is a screenshot of its original appearance in our very popular Christmas Puzzle week, which is still stored in the archives of the Wayback Machine:

We asked our readers to find enter some legal chess moves that let the game end on move five with the stipulated knight takes rook mate. The problem was given to me by British grandmaster and author John Nunn. He sealed the answer in an envelope and asked me to return it unopened, with the solution written on the back. Together with Ken Thompson, the famous computer scientist, I spent many hours trying to solve the problem (and Ken spent an hour trying to read the contents of the envelope over a bright light). In the end, we tore the thing open and admitted humiliating defeat.

The story of how this problem occupied my life is told in full in this 2013 article. It describes how in 1986 I gave the problem to Garry Kasparov and Anatoly Karpov to entertain them on a long car journey. It kept them busy during the ride and for the next couple of days in our hotel in Lausanne. They couldn’t solve it. Later, Garry shared it with former World Champion Mikhail Botvinnik and the students of their training camp. They were all stumped.

I published the problem in ChessBase Magazine 73 – offering a special prize of a book signed by some of the world’s top players, confirming that the winner is the greatest. The article was posted on a number of Internet chess platforms, where people launched concerted efforts to solve the puzzle.

I also posted it on my favourite site, the geek watering-hole Slashdot (“News for Nerds”), which is aimed at people who are interested in science, technology, computers, programming and weird stuff in general. A few hours after the slashdot posting a tsunami of emails overwhelmed me. I received a total of well over a thousand messages. One visitor, Ken Boucher, wrote: ’"Frederic, all of Slashdot went nuts thanks to you. When your puzzle was posted there, I and many others lost all productivity until someone managed to solve it. Brilliant sir, brilliant. Thanks for a reminder of why I used to play chess."

• Sample of reactions recorded in the Wayback Machine.

So here’s a live diagram on which you can try to solve the problem:

You can move the pieces, click on the notation button below the board to track your progress or to try alternate lines. The game should end on move five with knight takes rook mate.

2025 Christmas Puzzle 7

And here is a similar problem we published exactly ten years ago. It elicited close to a hundred feedback messages describing the trials and tribulations it had brought upon our readers. Hopefully it will not cause too much suffering, this time around.

***A game ends with the move 6...Nf1 mate. How did it go? ***

Here again is a board on which you can try to find the six moves. Note that the game ends with a black knight moving to f1, and, very importantly, it is not a capture! Our readers in 2015 came up with games that end in 6...Nxf1#, which is fairly easy – but not what we are looking for: just 6...Nf1#.

Please do not post any solutions in our feedback section below. Let other readers enjoy the problems. Please submit your solution feedback here. We will reveal the solutions to all Christmas Puzzle in the first week of January 2026.