Как и выигрыш ладьи путем Фe5+-xa1 вместо автоматического 3...Фа5

Тарраш - Любитель 1898 г.

1.e4 e6 2.d4 d5 3.Nc3 dxe4 4.Nxe4 Nd7 5.Bd3 Ngf6 6.Qe2 Nxe4 7.Bxe4 Nf6 8.Bxb7 Bxb7 9.Qb5+ Nd7 10.Qxb7

либо после текста с комментами еще и давать чистый. иначе текст нельзя загрузить в pgn-плагин внизу страницы.

1.e4 e5 2.Nf3 Nc6 3.Bc4 Be7
{ В этом дебюте игра приобретает более спокойный характер, чем в итальянской партии и защите двух коней. К венгерской партии обычно обращаются шахматисты, не желающие подвергать себя опасности острых дебютных атак. }
4.d4 exd4
{Основная стратегическая идея дебюта - удержание пункта е5. С этой целью продолжают 4...d6, после чего у белых два плана - 5.d5, придавая игре закрытый характер (далее возможно 5...Nb8 6.Bd3 Nf6), и 5.dxe5. После 5...dxe5 (5...Nxe5? по аналогии с вариантом защиты Филидора приводит к потере пешки - 6.Nxe5 dxe5 7.Qh5 из-за угроз 8.Qxf7+ и 8.Qxe5) 6.Qxd8+ Bxd8 7.Nc3 положение упрощается, но белые сохраняют некоторую инициативу. }
5.Nxd4 d6 6.O-O Nf6 7.Nc3 O-O 8.h3 Re8
{Сейчас (или на следующем ходу) следовало разменяться на d4 (8...Nxd4 9.Qxd4), а затем сыграть Be6.}
9.Re1 Nd7?
{Белые выигрывают с помощью типовой комбинации, используя тактическую слабость пункта f7 и стесненную позицию неприятельских фигур:} 10.Bxf7+! Kxf7 11.Ne6! Kxe6 12.Qd5+ Kf6 13.Qf5#

That is approximately the confidence number we give to our King's Gambit results: 99.99999999%. It might be that there is a flaw somewhere, but if there is it will not be discovered in the course of this universe – that would require more computational power than could ever be provided. And of course it is possible, and in fact very, very likely, that there is no flaw.

How much processing time went into your project?

Approximately – well actually quite precisely – 10,750,000 hours of single-core CPU time. The King's Gambit run took a little over four months in total, elapsed time, to calculate.

That was on about 3000 cores, right? What was the system doing?

Our algorithm works in an iterative manner – it first forms a hypothesis, and then it confirms or alters that hypothesis over a number of passes using a non-deterministic Turing Machine program running across the clusters. Interesting things happen within the algorithm, such as strategy stealing, which is kind of like null-move where you calculate what happens when you pretend to be the other side. This is coupled with a number of other innovations including advanced zugzwang detection techniques which allow us to establish if a position is a forced win or not. The time needed for each pass varies greatly from position to position. The algorithm never fails and runs in quasi-polynomial rather than exponential time. If it doesn't produce an initial hypothesis for some position in a reasonable amount of time then we have to consider the position as unsolvable with current resources.

What specifically were the results you calculated for the King’s Gambit? And why did you choose this opening?



Well, there were a number of reasons for choosing it. One was that 50 years ago Bobby Fischer published a famous article, A Bust to the King's Gambit, claiming to have done exactly that. I was curious to see how valid his conclusions were. Turns out they were amazingly accurate. The main line of the King's Gambit, 1.e4 e5 2.f4 exf4 3.Nf3, is indeed winning for Black. Moreover, the only winning move is 3... d6!, just as Fischer claimed. For instance the more popular 3...g5 allows White to draw after 4.h4! In fact, Fischer's main line holds up incredibly well: 3...d6! 4.Bc4 h6! 5.d4 g5! (an exclam denotes any move which gives a better theoretical result than every alternative), although some side-variations from his article do have inaccuracies.

Genius or luck?

Probably mostly luck. Naturally some of his lines are not accurate: they weave in and out of draws. But the main conclusion is correct.

So is the King's Gambit really busted?

No, just if White plays 3.Nf3. Incidentally 3.Bc4 loses as well to 3...Nf6! (incredibly every other move allows White to draw). But this is where the fun begins. It turns out that the weird looking 3.Be2! leads to a draw. In fact we found that 3.Be2! is the only move that avoids a white loss.

Very strange. Can you explain this?

That’s probably a task for a stronger chess player than I am. It's obvious that 3.Nf3 and 3.Bc4 both have some drawbacks which 3.Be2 avoids. The move isn't really a very consistent follow-up to 2.f4, but if we accept, in human terms, that 2.f4 is a mistake and try to make the best of it, then 3.Be2 looks more attractive.

Can the computer explain this in more concrete terms?

The computer's tree isn't especially insightful – it tells you what needs to be played in each position, but does not tell you why. “Because it is in my database of positions” is not an answer a human player is seeking. But you can try out lines to your heart’s content: after 3.Be2, Black has 30 legal replies, and 27 of them lead to a draw. This includes nonsensical moves like 3...h5 and 3...f6. After the most common move, 3...d5, White must play the obvious 4.exd5!, after which Black has 36 legal moves, 29 of which draw, again including nonsensical moves like 4...h5 and so on

C33: King's Gambit Accepted, Lesser bishop's (Petroff-Jaenisch-Tartakower) gambit - 1. e4 e5 2. f4 exf4 3. Be2 - Chess Opening explorer

Васик говорит, что решил королевский гамбит.

Движение в правильном направлении, указанном еще Бирюковым

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1.f4 d5 2.h3 c5 3.a3 e5 4.g4 Qh4# 0-1