An interesting article! Thanks for pointing out the fine points of an x-ray.
X-Ray Vision
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Seems the top players are very aware of the danger of x-rays and often try to preempt any potential problems.
In Fischer's "My 60 Memorable Games", he explains his 15th move Kb1 with "Amateurs are often puzzled by this apparent loss of time. Actually it is a handy defensive move, getting out of the pin on the c-file which could become annoying after ...b5-b4. One never knows when lightning will strike!"
You add a lot of value to these forums batgirl. Well researched, and much appreciated.
Jan 27, 2017
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#5
Nckchrls wrote:
Seems the top players are very aware of the danger of x-rays and often try to preempt any potential problems.
In Fischer's "My 60 Memorable Games", he explains his 15th move Kb1 with "Amateurs are often puzzled by this apparent loss of time. Actually it is a handy defensive move, getting out of the pin on the c-file which could become annoying after ...b5-b4. One never knows when lightning will strike!"
It would seem that the best way to avoid surprises is to eliminate the conditions. I suspect there are deeply hidden X-Rays and other tactics involved in calculations of which most of us are unaware from just playing through a game but which are factored in by these ultra-skillful players.
Jan 27, 2017
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#6
Woah thanks for this thread batgirl. I found myself with some unanswered questions as well after responding in that other thread. This really helped to clarify some things.
batgirl wrote:
It would seem that the best way to avoid surprises is to eliminate the conditions. I suspect there are deeply hidden X-Rays and other tactics involved in calculations of which most of us are unaware from just playing through a game but which are factored in by these ultra-skillful players.
I guess computers might like to squash potential x-ray problems as well. Upon reviewing some relatively recent computer vs. computer games, just came upon this Rybka anti x-ray 19th move versus Komodo:
Jan 28, 2017
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#8
Another good thread by Batgirl.
Personally, I differentiate between pins, skewers and X-rays. All different tactics. But that's just me...
Feb 14, 2017
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#9
pins and skewers are only alike in style, but skewers and x-rays often seem to be one and the same.
I remember an example from some book I read maybe 20 years ago that showed a Bishop x-raying a Rook through a whole like of pieces occupying the diagonal. I considered that example a true x-ray because the attack was always there (the X-Ray) but it took a series of tactics and equal exchanges to actually expose the attack and win the exchange.
I also think of pins, skewers, and x-rays as 3 different tactics (except in the case where, say, a bishop attacks 2 rooks on the same diagonal, which could be either a pin or a skewer, since the 2 enemy pieces have the same value).
For me, pins and skewers involve 3 pieces in a line, where the attacking piece is at one end, and the 2 attacked pieces are at the other end. So if a White piece is pinning or skewering black pieces, then the color arrangement along the line is W-B-B or B-B-W (depending on which direction you are looking).
But an X-Ray, as I see it, is actually a form of defense/guarding, where one piece of a certain color is "guarding" another piece of the same color, that is on then same line, but in a circumstance where a piece of the opposite color stands between the "guarding" and "guarded" piece, on the same line. Moreover, that enemy piece which stands between the friendly pieces is also capable of capturing at least one of the 2 "friendly" pieces on that line. In this configuration, the sequence of colors along that line would go something like W-B-W, or B-W-B.
Thus, for me Batgirl's 3rd example in the original post, from Max Euwe vs. Rudolf Loman, includes an X-Ray defense of the White queen on h8 by the White bishop on b2. And in the example from Bobby Fischer vs. Arthur Bisguier, White's queen and rook are mutually defending one another ("through" the Black queen), with X-ray defenses going in both directions.
But just about all the other examples, for me would be either pins or skewers (more often skewers) - or in the very first example, both (the white bishop can be seen equally as pinning one black rook to the other, or skewering one black rook through the other)...
I realize there is no universally agreed upon definition of the X-Ray, unlike some other common tactical motifs, but I prefer to avoid redundancy between X-Ray and skewer or pin. Or rather, ,y first preference would be to restrict X-Ray to just the case where one piece defends another friendly piece "through" an enemy piece, and my second preference would be to say that all 3 types of scenario could be called X-Rays (in which case pins and skewers are subsets of a more inclusive, broadly defined category of "X-Ray motifs". But what I don't really understand is the tendency to say that X-Rays could include either skewers or straight-line defenses "through" an enemy piece, but do not include pins...
Obviously it's just a matter of personal preference, and probably depends on what definition or explanation of the term one first encounters...
Feb 14, 2017
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#11
Did you see these recently posted games with true x-rays, batgirl? I've started saving such games since true x-rays are fairly rare.
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https://www.chess.com/forum/view/game-showcase/slippery-opponent
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https://www.chess.com/forum/view/game-showcase/long-king-walk
After reading recent thread on the X-Ray Attack (https://www.chess.com/forum/view/general/something-about-x-ray), I looked into some examples on my own as well as what some authors had to say about it. Here's some of what I found:
Most authors equate an X-Ray with a Skewer, such as:
But this seems to be too simplistic and maybe even inaccurate.
There seems to be at least two different kinds of X-Rays: one in which the skewered piece is of LESS value than the the other attacked piece.
or the final attack is on a square, not a piece.
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Here's an intriguing position given in a very nice book, "Tune Your Chess Tactics Antenna" by Emmanuel Neiman.
The Black's Queen wants to check on h1 at which point she would X-Ray White's Queen (skewer the King). But White's Queen is protected by the Bishop on e3. So, a deflection is needed first.
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Fischer finds an X-Ray in this "juicy" position against Art Bisguier. White X-Rays d7 to win a pawn and a better position with 34. Rxd3:
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In "Mastering Chess" by Kopec, Chandler and Morrison, they equate the "X-Ray" with the "Skewer" and give this interesting example of a "saving" X-Ray:
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Every pawn is a potential queen. If you can get a pawn tot he eighth rank and promote, you will gain a decisive mterial advantage. Here Black has two so-called passed pawns running free to queen.
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In "Pandolfini's Ultimate Guide to Chess" Mr. Pandolfini says,:
I'd like you to learn about the x-ray attack, which some people call a hurdle.
The basic kind of x-ray -though not the only kind- involves two units of one color and one of the other color, all three occupying and having the ability to move along the same line.
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Sometimes the x-ray doesn't concern three units on the same straight, but two units and a key square on the line in question.
An x-ray attack on the d8 square:
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In 1953 the irrepressible Al Horowitz wrote the following brief but sparkling article on X-Rays:
The lines of force of the major pieces, the Queen and the Rook, and of the Bishop are continuous to the very edge of the hoard. A Queen on h1, for example, attacks every square on the file, from to h1 to h8, every square on the diagonal, from h1 to a8. and every square on the rank, from h1 to a1. When a unit obstructs such a line of force, it merely interrupts it; and the force automatically persists when the obstructing unit moves.
Because of this characteristic of Queen, Rook and Bishop, the tactical motif, the X-Ray Attack, comes into being. The X-Ray, called by some authors the skewer, is really a piercing attack, directly striking upon a front man and penetrating beyond, in its effect, to a rear man on the same line of force. Thus, when the front man gives way, the rear one is vulnerable.
In a way, the X-Ray is like the pin. The main difference between the two is the comparative values of the front man under attack and of the rear man. In a pin, the front man is generally the less valuable. Hence it stand, by necessity to shelter its more important colleague, and on becomes pinned. In the X-Ray, the opposite condition obtains. So the front man is perforce moved, letting the rear man fall in a choice of the lesser evil.
White comes out a piece ahead after a mating net, a discovered check and an X-Ray attack all play a part. What is noteworthy, however, is that, the other factors aiding, White creates his X-Ray attack practically out of thin air.
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The X-Ray in Reserve
The position below has occurred time and time again.
It's interesting to note that if h7 or g7, White could not win.
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The X-Ray that Failed
White has a clear cut win in the next position by straightforward means. But he is imbued with the power of the X-Ray, or thinks he is. So he advances:
Had White omitted capturing Black's Rook, the position is a theoretical draw. Stalemate, one of the tactical motifs, invalidates many a plan.
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An X-Ray Finale
White seems to be in a sorry mess in the following position. But again, all is not what it seems. Where there's a will, there's apt to be something relative. Here White works from clause to cluse to codicil. It is White's move.
White comes out a piece ahead after a mating net, a discovered check and an X-Ray attack all play a part. What is noteworthy, however, is that, the other factors aiding, White creates his X-Ray attack practically out of thin air.
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A Beam of X-Rays
Here again, White's position is all too perilous. It is either mate of be mated.