King's Indian Defense: 9...a5 and the Trust Problem Called the Bayonet Attack

Move 22 of an open-section game in Chengdu this autumn: White had 41 minutes left, Black had 9. White played 9.b4 — the Bayonet Attack, the familiar thrust into the queenside in the King's Indian Defense. Black answered 9...Nh5, entering a road every database has long since recorded. The two players moved like machines for 18 moves, then collapsed together over the next four. I pressed the clock, logged thinking time per move into my spreadsheet, and the numbers came out cold: 34 minutes for 18 theoretical moves, 6 minutes for everything else. They did not lose because they miscalculated. They lost because they burned all their time on moves someone else had already written. That moment is what drew me to a theory product being marketed as an antidote to the Bayonet: an instructional disc advocating 9...a5.

To understand why a ninth move deserves discussion, it has to be placed inside the right structure. The King's Indian Defense, Mar del Plata branch, runs 1.d4 Nf6 2.c4 g6 3.Nc3 Bg7 4.e4 d6 5.Nf3 0-0 6.Be2 e5 7.0-0 Nc6 8.d5 Ne7, sitting in the ECO E97 to E99 range. Its signature is a deliberate trade: Black concedes the center early, then counterattacks with ...e5 and ...f5, turning the game into a two-wing race in which whoever opens first wins.

White's 9.b4 — the Bayonet Attack — has been the fashionable answer of the last two decades. White pushes a pawn to seize queenside space, preparing b4-b5 to crack Black's structure. The main reply, present in almost every manual, is 9...Nh5: Black opens the position, forces the lines, and pushes both sides into a theoretical jungle. The product now being promoted proposes a different route — 9...a5. Instead of charging into the center, Black attacks the very b4-pawn that just advanced, steering toward a more closed, more strategic, less concrete game.

According to the promotional description, 9...Nh5 opens the position, forces the lines, and makes computer analysis important again. Meanwhile 9...a5 leads to sound positions with very few concrete lines. That is a strategic argument, not a theoretical novelty. The product does not claim to invent a new move; it claims to sell psychological comfort, aimed at players who prefer thinking for themselves over memorizing.

This is where I open the spreadsheet. I found no engine evaluation, no sample games, no average centipawn loss, no win rate, no draw rate. The product promises "very few concrete lines" but offers not a single figure to prove it. For someone who reads data for a living, that is a striking gap. In my personal file on the Mar del Plata branch I keep more than a thousand club-level and elite games, and what I learned is this: a move does not create peace by itself; only a well-prepared player does. 9...a5 is a known sideline, not an invention. It has appeared in practice, and it does not remove calculation; it merely relocates calculation from a sequence of moves to an assessment of the position.

The claim that "both sides have equal chances" is a positional statement, not a proof. Balance on the board is debatable; balance in sales copy always tilts toward the seller. And when a product says its move makes White "quickly dangerous to himself if Black knows what to do," I read that as expectation inflation, not a technical conclusion.

There is one technical detail the advertising omits, and it matters more than any promise. After 9.b4 a5, White can close the queenside with b5 and shift focus to the kingside, or keep the tension by defending the b4-pawn and opening lines for the heavy pieces. In both directions White is not passive; White is merely forced to choose. That is the big difference between a strategic branch and a forcing branch: in a forcing branch you lose your options but know the price in advance; in a strategic branch you keep your options but pay for them in clock time.

The most contentious line is this one: computers often do not know how to handle such complex strategic positions. That is pre-AlphaZero language. Today's neural-network engines handle the long-term strategic positions of the King's Indian far better than that sentence implies. The argument that "humans beat machines in closed positions" is out of date, and using it to sell a product is a sign of lazy updating, not of theoretical depth. It may still appeal to club-level buyers — the people who genuinely struggle with low-theory positions — but it does not describe the reality of a modern analysis room.

Then there is an issue I care about more than all the rest: source quality. The promotional package I received carried a headline about a team round in Samarkand, with "all the top teams winning," while the entire body was a blurb for a DVD about 9...a5. Two unrelated texts had been spliced together. For a working writer, that is a red flag. When the headline and the body do not match, the first thing that loses value is not the move but the credibility of the document itself. Anyone citing this package without checking the original source is passing on a distortion.

What deserves saying is that 9...a5 is not meaningless in itself. It is a legitimate branch, and for players unwilling to memorize the first twenty moves of 9...Nh5, it is a practical choice. Its real value lies in steerability, not theoretical superiority. But that value exists only under one condition: the player must accept that White still has a position, still has a plan, and can still find a path if well prepared. No antidote erases calculation in a system designed to make both sides charge at each other.

A word about the other side of the market is also needed. Elite Bayonet players do not sit still. The history of opening theory shows that every "antidote" generates a counter-response within one or two theory cycles. If 9...a5 gets played often, analysis rooms will add plans for White, and then Black must find something new in turn. This is the ordinary spiral of the chess world, not the mark of a turning point.

I keep my old habit: after every major event, I re-check my models against fresh data. If 9...a5 appears in top-level games and holds up, I will log it. If it disappears after one theory cycle, I will log that too. Everything on the board is data waiting to be read — if you are willing to sit down. The final question is not whether 9...a5 is strong. The question is whether you are buying a move, or buying time to think for yourself?