Pandolfini's Puzzler #42 - Trivial or Quadrivial?
Professor: Welcome, class. Are you ready for some chess?
Class: Yes we are, Professor.
Professor: I thought today we’d take it easy and look at a few trouble-free problems, nothing special. With various tournaments coming up, it can’t hurt to stay sharp.
Hale: What kinds of problems, Professor?
Professor: Oh, simple tactics.
Lucian: What kinds of simple tactics?
Professor: Oh, uncomplicated ones. Maybe nothing more than rooks and knights at play.
Ryan: OK. I’m ready. Show us what you have.
Professor: Well, let’s start with this undemanding miniature and go from here.
Question 1: What is White’s best move?
Hale: That’s ridiculously simple. Although I do like the final position, as simple as it is.
Zephyr: Let’s see another plain one.
Professor: OK. You’ve asked for it. White mates in two moves, but there are two ways to do it.
Question 2: What are White’s two best moves?
Ryan: One of them is easy. In fact, it’s really primitive.
Lucian: You mean like ancient? Or do you mean like for Neanderthals?
Hale: I don’t mean whatever you just said. Besides, Neanderthals were actually pretty smart.
Zephyr: Yes, but very few of them could play chess.
Professor: Well, let’s see if your evolved status can help you solve this next one.
Question 3: What is White’s best move?
Lucian: You must be kidding, Professor. This, too, is so unsophisticated.
Hale: I agree with Lucian, and I don’t always agree with Lucian.
Zephyr: I agree with Hale, and I don’t always agree with Hale.
Professor: All right, I’ll tell you what. I also feel like being agreeable. Let’s take away Black's rook and knight and make it even less convoluted.
Question 4: Can White stop Black’s pawn?
Zephyr: You know, Professor, this may look slightly more complex, but it’s just as trivial as the other three problems.
Professor: Is it that trivial?
Ryan: No, it’s not that trivial. I’d say it’s more quadrivial.
Answer below - Try to solve ProfessorPando's Puzzle first!
For diagram 1, the answer is 1. Rd5+! Nxd5 2. Nc6 mate.
In diagram 2, there are two mates in two. Ryan found 1. Rh7+ Nxh7 2. Nf7 mate. And Zephyr found 1. Nf5+ gxf5 2. Rf6 mate.
In diagram 3 White wins with 1. Kb2!, creating a kind of zugzwang. Since Black can’t move the knight without allowing 2. Rb8 mate, he must drop the Exchange by 1…Ra7. After 2. Nxa7, White should win from there.
In the 4th diagram, White saves the day with 1. Nb5!. Assuming Black promotes, 1…c1/Q+, White has 2. Nc3+. Two variations then lead to a quick victory for White:
If 2…Qxc3, then 3. Kxc3 Ka3 4. Ra5 mate.
And if 2…Ka3 instead, then 3. Ra5+ Kb2 4. Ra2 mate also does the trick.
A terrific cache of rook and knight vs. rook and knight endgame shots can be found in Van Perlo’s “Endgame Tactics: A Comprehensive Guide to the Sunny Side of Chess Endgames.” Beyond that section, the book is a wonderful resource for surprising endgame devices and ploys. An earlier work that inspired the same love for endgame stratagems is Jenö Bán’s “The Tactics of End-Games.” It too offers a hoard of insightful endgame ruses.