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I have three chess puzzles for you this week, but you dont need to know the rules of chess for two of them. These two are variants of the famous eight queens puzzle, which asks solvers to position eight queens on an eight-by-eight board such that no two queens attack each other. The eight queens puzzle requires a little too much trial and error for my taste, which perhaps is why the problem more often shows up in computer science courses as an exercise in writing programs that search through cases for you.

Would Peter Capaldi Return to Doctor Who?

The world of chess puzzles is full of beautiful and often humorous constructions, but sometimes one needs extensive experience to solve or even appreciate them. The most common type of chess puzzle depicts a position and challenges solvers to force a checkmate in a given number of moves. This weeks third puzzle throws a delightful twist into this standard genre, instead asking you to find a move that does NOT instantly checkmate. Youll need to know the rules of chess for this one. As chess puzzles go, its not exceedingly difficult, but hopefully gives a flavor for how amusing these compositions can get.

Did you miss last weeks puzzle? Check it out here, and find its solution at the bottom of todays article. Be careful not to read too far ahead if you havent solved last weeks yet!

Composed by Karl FabelGraphic: Jack Murtagh

Ill be back next Monday with the answers and a new puzzle. Do you know a cool puzzle that you think should be featured here? Message me on Twitter @JackPMurtagh or email me at gizmodopuzzle@gmail.com

Did you solve last weeks puzzle in time?

You sell calendars without years written on them. If somebody wants a 2024 calendar, you give them one whose days of the week match up correctly with 2024 (January 1st is a Monday, January 2nd is a Tuesday, etc.)

Find the answers below. Shout-out to PeterE for sniping all of them and for calling the Gregorian calendar Greggys system.

1. There are 14 different calendars. Years can begin with any of the seven days of the week, and years either have 365 days or 366 days (leap years). This results in 14 total possibilities.

2. 2034 is the next time the 2023 calendar will be used again. Every non-leap year that passes, the days shift forward by one. Think of it this way: 2023 began with a Sunday, and every seven days after that, the week resets to Sunday (Jan 8th, Jan 15th, etc.). So starting with the 1st and adding any number thats divisible by seven (7, 14, 21, 28,...) gets you back to Sunday. 364 is divisible by seven (7 x 52 = 364), so adding that to 1 yields 365, the last day of the year. This means December 31st was also a Sunday, leading to 2024 beginning with a Monday. All non-leap years work like this. After a leap year, the days shift forward by two because of the extra day.

With this in hand, we can calculate when the 2023 calendar (non-leap year beginning with Sunday) will recur. Days shift forward by 1 each year, except after a leap year, when they shift forward by 2:

Since 2034 is not a leap year and begins with a Sunday, it uses an identical calendar to 2023.

3. The largest possible gap between uses of the same calendar is 40 years. You wouldnt be alone if you came up with 28. Ill explain why 28 is a natural guess and then how the gap can actually be as large as 40.

Leap years are rarer than non-leap years, so it stands to reason that gaps will be larger between leap years. After a leap year, the subsequent years shift days according to the pattern: 2, 1, 1, 1, 2, 1, 1, 1, and so on (you can see this in the table above starting at 2025). So every leap year (every four years) is five days shifted forward (2+1+1+1) from the previous leap year (e.g. 2028 is the leap year after 2024 and it begins with a Saturday, five days after 2024s Monday). Starting at a leap year, every four years, the days shift forward by five and you need to do this seven times before cycling back to the same starting day. It takes 28 years to pass through seven leap years (indeed, 2052 is 28 years after 2024 and the first leap year after it to begin with a Monday).

One huge exception can extend or shrink this number. Years divisible by 100 skip a leap year (unless theyre divisible by 400). 2100, 2200, etc. will not be leap years. Consider the 2072 calendar: a leap year which begins on a Friday. 28 years later will be 2100 and will also begin on a Friday, but its not a leap year! Wed have to continue 12 more years before repeating the 2072 calendar in 2112.

Read more here:
Gizmodo Monday Puzzle: You Don't Have to Play Chess to Be the Queen - Gizmodo

GM Ray Robson did it again, winning his fifth consecutive title at the 2024 Puzzles World Championship. The undisputed G.O.A.T. of Puzzle Rush has won every edition of this tournament since it started in 2020.

This seemed to be his toughest year yet, however, as he faced 14-year-old up-and-coming IM Andy Woodward in the Grand Final. The youngster had a great tournament and even took an early lead against Robson, but the reigning champion then won four points in row to reclaim his crown.

On the previous day, eight players qualified from a field of 99. While solving 56 (!) puzzles in three minutes was the minimum needed to reach this stage, day two would be even more challenging for the young tacticians. Robson and Woodward, the top two seeds, proved to be top two best puzzle-solvers on Friday.

The eight players competed in a Puzzle Battle double-elimination bracket, with best-of-eight matches in the Winners Bracket and best-of-four in the Losers. A notable difference was that players solved the same puzzles as their opponent on day two.

In the first round, all the players started in the Winners Bracket and played a best-of-five series to determine their placements in the next phase.

Standings After Winners Quarterfinals

Robson had the most dominant performance, sweeping all five rounds, with a high score of 57, against the talented 17-year-old prodigy GM Christopher Yoo. Displaying his tactical prowess, Woodward was the only other player to match the high score of 57, as he defeated GM Hans Niemann 5-2.

In the following clip, we can see both tactical wizards achieving the same score back-to-back.

Woodward continued to showcase his puzzle mastery in the next round against Xiong, where even after making two early mistakes he was still on par with his super-GM opponent.

Woodward ultimately lost that match, but he went on to later defeat Xiong convincingly, 2.5-0.5, in their rematch in the Losers Final.

Now let's see if you can solve some of the puzzles the experts got wrong. (You'll have a bit more time than they did to solve them!)

The following puzzle was Niemann's third mistake (on puzzle #56) in round two against GM Raunak Sadhwani. How do you fare? Black to move.

Against Robson, GM Pranav V made his third mistake (on puzzle #50) in round six. Can you improve on his move? Black to move.

It needs to be mentioned that Niemann initially appeared to have been eliminated by Raunak due a website bug. Niemann's actual score was displayed incorrectly; he reported the issue, and after investigation, the score was corrected and the result was overturned.

That victory was short-lived anyway, as Pranav eliminated Niemann in dramatic fashion in the match that followed. Pranav led 2-1 in a first-to-2.5 format, which meant a draw was equivalent to a loss for Niemann. In the final seconds, Niemann needed to risk getting one wrong to avoid that very situation, with both players on 50 correct puzzles against two misses. Taking that risk is easier said afterward than done in the moment, and time ran out, allowing Pranav to advance by the skin of his teeth.

As for short-lived victories, Pranav himself was eliminated in the following match by the surging Woodward. It lasted just three of the four rounds and Woodward put up a monstrous 58 score in the final battle.

Meanwhile, Robson won the Winners Final by defeating Xiong with a dominant 5-1 score. The 23-year-old super-GM Xiong got a second life against Woodward in the Losers Final, but the young gun needed just three rounds once again to win the match.

Fate was cruel to Xiong in the last round, as Woodward struck out on puzzle #48 and his opponent could have simply not solved it and claimed a round win. Instead, Xiong attempted to solve the puzzle and also struck outand a draw meant Woodward advanced.

Well, do you think you can solve puzzle 48, the one both players failed? Black to move.

The Grand Final could hardly have started better for Woodward, but his explanation after the match illustrates what went wrong: "I guess I was getting kind of excited and then that's where it started going wrong. I started mouse slipping and making pretty bad mistakes. I guess that's one thing to be improved for next year."

I guess I was getting kind of excited and then that's where it started going wrong.

Andy Woodward

He built a commanding two-point lead against Robson after putting up 59, his personal best, two times. At first, it seemed like an upset was in the making...

... but Robson proved to be the more consistent solver, scoring at least 50 in every round, while Woodward's scores dipped into the 40s and even 30s. First, Robson evened the match at 3-3...

... then, he won two more in a row to take the match.

Robson wins $5,000 for his first-place finish while the runner-up Woodward takes home $4,000.

After the match, Robson was full of praise for his teenage opponent, saying: "I know he can actually maintain this sort of level of getting to like 55+ pretty consistently when he's doing well. So I was actually pretty fortunate that he dropped off in the last few."

He also admitted that nothing lasts forever, that the next generation will soon be knocking on the door.

It's a remarkable achievement for Robson, who proves year after year that he's the best there is at Puzzle Rush and Puzzle Battle. As for Woodward, he plans to be back next yearwhen he promises to be an even more formidable rival.

The 2024 Puzzles World Championship (PWC) is a competition for the best chess tacticians in the world. The event is a part of the Puzzle Week celebration and happens on January 11 and 12, starting at 12 p.m. ET/18:00 CET. The PWC features a $25,000 prize fund.

Previous coverage:

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Puzzles World Championship 2024: Robson Wins 5th Consecutive Title, Beats Young Gun - Chess.com

At just 20 years old, both Tye and Kade Ruotolo have proven time and time again that theyre two of the best jiu-jitsu competitors in the world today.

While some may look at their age as a disadvantage, the two brothers have shown plenty of times that they do not have a lack of experience, thanks to how long they have been dedicated to this pursuit.

Theyre always able to stay multiple steps ahead of their opponents even when there is a large age gap, and that speaks to the incredible minds that both men have for jiu-jitsu.

Kade explained the love and pursuit of perfection in grappling during their recent appearance on The Fighter and The Kid podcast.

The ONE lightweight submission grappling world champion says that while he and his brother still have a lot to learn, their years on the mats with each other have put them both at the highest level:

Watch the full interview below:

With his brother Tye in possession of the welterweight title, Kade is the reigning ONE lightweight submission grappling world champion and has an upcoming title defense on the horizon.

He will face off with Tommy Langaker for a second time at ONEs return to Japan on January 28 for ONE 165.

The champion has beaten Langaker once before but this time around, the Norwegian competitor is motivated by his setback that occurred last time out against Ruotolo.

ONE 165 will air live at Asian prime time on January 28. Check your local listings for more details.

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You're always trying to guess your opponent's next move Kade Ruotolo equates jiu-jitsu to a game of chess - Sportskeeda