Checkless Chess

dawson checkless chess puzzle

In checkless chess it’s illegal to give check without giving checkmate. This changes the whole complexion of the game. T.R. Dawson published this example in Die Welt in 1951. White is to mate in two moves.

The answer, 1. f6, threatens 2. Qf5, which strangely is mate because the black king can’t move off the long light diagonal, since that would discover check by the black bishop without giving checkmate. Black can try to prevent this finish by playing 1. … Qc8, guarding f5 and thus making 1. Qf5 itself illegal. But this permits 2. Nxd6, which now is mate because the black king has nowhere to run on the long diagonal and 2. … cxd6 is illegal because this would give a mateless check.

Similarly, if Black tries to stop 1. Qf5# with 1. … Qxf6, then 2. Nc5 is mate because Black can’t capture the knight — again, this would expose White’s king to an illegal check. And if Black tries to answer White’s first move with 1. … d5, to block the long light diagonal and free his king to flee elsewhere, then White can play 2. Qe5#, an ordinary (and legal) mate.

| Puzzles

Lost Lessons

THOUGH I can never pay enough to your Grandfather’s Memory, for his tender care of my Education, yet I must observe in it this Mistake; That by keeping me at home, where I was one of my young Masters, I lost the advantage of my most docile time. For not undergoing the same Discipline, I must needs come short of their experience, that are bred up in Free Schools; who, by plotting to rob an Orchard, &c. run through all the Subtilties required in taking of a Town; being made, by use, familiar to Secresie, and Compliance with Opportunity; Qualities never after to be attained at cheaper rates than the hazard of all: whereas these see the danger of trusting others, and the Rocks they fall upon, by a too obstinate adhering to their own imprudent resolutions; and all this under no higher penalty than a Whipping: And ’tis possible this indulgence of my Father might be the cause I afforded him so poor a Return for all his Cost.

— Francis Osborne, Advice to a Son, 1656

| Society

Opaque Sets

https://commons.wikimedia.org/wiki/File:Unit_Square_Opaque_Forest_Solutions.svg

A creature living in the plane can’t see through a unit square — the square’s four line segments block its line of sight from any angle. Is there a way to achieve the same result using fewer building materials? Removing one of the square’s sides does the job — this requires only 3 units of line segment and still prevents anyone from seeing across the square’s area. The arrangement at lower left does better still, requiring only about 2.732 units. And the one at lower right requires only about 2.639 units.

Is that the shortest possible opaque set for the square? Possibly — but no one has been able to prove it.

| Science & Math

Brute Force

NBC’s Today Show had a surprising guest in 1959: G. Clifford Prout Jr., president of the Society for Indecency to Naked Animals, an activist group that hoped to clothe “any dog, cat, horse or cow that stands higher than 4 inches or longer than 6 inches.” Prout’s bizarre cause earned him regular media attention, and the society’s newsletter published this anthem:

High on the wings of SINA / we fight for the future now;
Let’s clothe every pet and animal / whether dog, cat, horse or cow!
G. Clifford Prout, our President / he works for you and me,
So clothe all your pets and join the march / for worldwide Decency!
S.I.N.A., that’s our call / all for one and one for all.
Hoist our flag for all to see / waving for Morality.
Onward we strive together / stronger in every way,
All mankind and his animal friends / for SINA, S-I-N-A!

Of course it didn’t last. When Walter Cronkite interviewed Prout in 1962, one of his staff realized he was really actor and screenwriter Buck Henry. The hoax had been masterminded by serial prankster Alan Abel. “When Cronkite eventually found out that he’d been conned, and I was the guy behind it, he called me up,” Abel recalled. “I’d never heard him that angry on TV — not about Hitler, Saddam Hussein, or Fidel Castro. He was furious with me.”

| Hoaxes

One Last Christmas Quiz

The Royal Statistical Society’s 2024 Christmas Quiz consists of two parts, a warmup section and the quiz itself, each consisting of 12 questions. Solvers (and teams) have until January 5 to submit their solutions, and the top three entrants will win a donation of £150, £120, or £90 to the charity or good cause of their choice. Updates and corrections will be posted on the competition website, and solutions will be published in January, together with the names of the winners.

| Puzzles

Misc

  • Samuel Johnson said that sending a timid boy to a public school is “forcing an owl upon day.”
  • Inscribed over the door of the library at Murcia, Spain: “Here the dead open the eyes of the living.”
  • TRICE in Pig Latin is ICE TRAY.
  • 35 × 1482 × 9760 = 3514829760 (Jean-Marc Falcoz)
  • “Mauve is pink trying to be purple.” — Whistler

Pekwachnamaykoskwaskwaypinwanik Lake is a lake in Manitoba. Its name is Cree for “where the wild trout are caught by fishing with hooks.”

Muckanaghederdauhaulia, a townland in County Galway, means “pig-marsh between two sea inlets.”

Saaranpaskantamasaari, an island in northeastern Finland, means “an island shat by Saara.”

Mamungkukumpurangkuntjunya is a hill in South Australia. Its name means “where the devil urinates.”

(Thanks, Colin.)

| Language · Literature · Quotations · Science & Math

Unfinished

During the Black Death, Florentine chronicler Giovanni Villani wrote, “The priest who confessed the sick and those who nursed them so generally caught the infection that the victims were abandoned and deprived confession, sacrament, medicine, and nursing … And many lands and cities were made desolate. And this plague lasted till ________.”

He left the blank so that he could record the date of the plague’s end, but then he himself succumbed, dying in 1348.

| Death · History

Oh All Right Then

https://commons.wikimedia.org/wiki/File:King_Charles_II_by_Adriaen_Hanneman.jpg

Another and still more amusing instance of self-revelation may be found in a manuscript familiar to many who have visited the Bodleian Library at Oxford. There, among other precious treasures, is a collection of notes scribbled by Charles II. to Clarendon, and by Clarendon to Charles II., to beguile the tedium of Council. They look, for all the world, like the notes which school-girls are wont to scribble to one another, to beguile the tedium of study. On one page, Charles in a little careless hand, not unlike a school-girl’s, writes that he wants to go to Tunbridge, to see his sister. Clarendon in larger, firmer characters writes back that there is no reason why he should not, if he can return in a few days, and adds tentatively, ‘I suppose you will go with a light train.’ Charles, as though glowing with conscious rectitude, responds, ‘I intend to take nothing but my night-bag.’ Clarendon, who knows his master’s luxurious habits, is startled out of all propriety. ‘Gods!’ he writes: ‘you will not go without forty or fifty horse.’ Then Charles, who seems to have been waiting for this point in the dialogue, tranquilly replies in one straggling line at the bottom of the page. ‘I count that part of my night-bag.’

— Agnes Repplier, Essays in Idleness, 1893

| History