9...a5: The Ledger of a Practical Antidote to the Bayonet Attack in the King's Indian

It was past six in the evening on the second floor of the federation hall in Purana Paltan. The fifth round of the 2026 Premier Division Chess League was running, and the sixteen-year-old seated at the board in front of me was showing me his preparation notebook, seven pages in a row. Every page was covered with a single phrase: 9...Nh5. He said, Sir, if White plays the Bayonet, I know nothing beyond this. I still have a photo of that notebook on my phone. Three years later, in early 2026, when I read a training DVD's advertisement claiming the real antidote to the Bayonet Attack was 9...a5, the first thing that came to mind was that boy's face at Purana Paltan. The notebook says one thing; the tape says another — and this advertisement seems to want to package and sell the exact opposite side of that boy's seven pages. This is where my work begins. The context needs to be made clear, because although the name King's Indian Defense is familiar to many chess players, its Mar del Plata branch is a separate world. After 1.d4 Nf6 2.c4 g6 3.Nc3 Bg7, Black concedes the centre and then strikes at it with ...e5. This is a classical example of the hypermodern idea. Then 4.e4 d6 5.Nf3 0-0 6.Be2 e5 7.0-0 Nc6 — this position is the Mar del Plata. The name comes from the Argentine seaside city, because a tournament held there in 2026 established this branch forcefully. Its core character is mutual wing attack: White pushes on the kingside, Black on the queenside. Both sides launch their own attacks, and the question is who arrives first. The most popular and sharpest line in this branch is the Bayonet Attack — 9.b4. This move is simple but poisonous. With b4 White takes space on the queenside, so that Black's ...b5 and ...c5 counterplay can be suppressed, and later c5 can be pushed to weaken Black's centre. The name Bayonet Attack comes from the knife-like thrust of this b4. The line saw much bloodshed in the sixties and seventies, then revived in the computer era, because engines showed White gets real chances here. Black's traditional reply is 9...Nh5. This move leaps the knight toward the kingside, usually with the ideas ...f5 and ...Nf4, and the position opens up, taking a forcing and tactical shape. Here lies the problem: the memory burden in this line is enormous, because the Bayonet Attack interferes with Black's ideas and computer analysis becomes important again. For a club-level player this is a difficult test. Against this background a DVD has come to market, whose advertisement says the solution here is 9...a5. It claims this move is an antidote to the Bayonet Attack — one that avoids the main line's forcing calculations and brings Black into a strategic, understanding-based position. The advertisement further says there are very few concrete lines here, the positions are sound, and objectively the chances are equal — although if Black knows the plans, things might quickly become dangerous for White. Now let us open the ledger. What does 9...a5 actually do? It takes space on the queenside, challenges White's b4 with ...a4, and prepares to break with ...b5. The move is not new. In the Bayonet branch of the King's Indian it is a long-established sideline, used mainly to avoid the forcing paths of ...Nh5. The DVD is probably presenting established theory in a new wrapper. Here is the first informational caution: calling it a novelty would be wrong. The second layer is more important. The entire sales pitch of this DVD rests on a practical-versus-objective framework. An objective evaluation means an engine-agreed evaluation; a practical evaluation means the reality of human play — the memory burden, the time pressure, the opponent's unfamiliarity. In the training-materials market this framework is not new. Sellers say the position is equal, but the opponent does not know what to do. This is a marketing device, not a proven evaluation. The third layer is the trade of memory for understanding. In 9...Nh5 Black must memorise forced lines, calculate, keep pace with the engine. In 9...a5 Black relies on long-term strategic planning — ...a4, ...b5, queenside disruption, a slow counter in the centre. For those who want to play by understanding rather than by memory, this trade is attractive. In my experience, many players from club level to International Master look for exactly this escape from forcing lines. The fourth layer is the most uncomfortable. This DVD nowhere gives an engine evaluation, nowhere gives a sample game, nowhere gives database statistics — neither win rate, nor draw rate, nor average centipawn loss. All claims are qualitative. In the advertisement's language the chances are equal, but behind that equality there is no proof. In the history of training materials this is not unusual, but as a beat keeper my notebook says one thing and the tape says another — and the tape is silent right now. The fifth layer is the market. Opening theory is a mature, deeply analysed market. When a main line becomes over-analysed, sidelines are re-marketed as antidotes. This is a cycle. The DVD format itself is an old distribution channel, now competing with subscription-based course platforms. So this product is probably not new theory, but a re-release of old theory. The sixth layer — and this is the biggest red flag. The article's title says ChessMom returns, supporting mothers on and off the board. But the content is entirely a King's Indian Defense DVD recommending 9...a5. This mismatch between title and content proves there is confusion in the packaging. Either the title is recycled, or the product's true identity is something else. Here verification is essential before using any information. I never rely only on a reporter's notebook. Between 2026 and 2026 there was no home Grandmaster norm tournament in Bangladesh, and after 2026 no new Grandmaster arrived — I verified these facts from federation documents, not from memory. Likewise, to verify this DVD's claims one must run an engine, cross-check a database, and see how 9...a5 actually scores in real play. Without verification it cannot be called theory, only advertisement. Here is my disagreement. The advertisement says computers often do not know how to handle these complex strategic positions. That claim is outdated and overstated in the engine era. Modern engines handle the closed positions of the King's Indian well, and they even see the slow queenside disruption. This is not a technical claim; it is rhetoric. A reader who takes this sentence as truth and builds his preparation on it will be misled. Another confusion spreads the idea that 9...a5 is a new discovery. It is not. It is a known weapon against the Bayonet, living in the shadow of the mainstream. The DVD is selling it in new colours. There is no fault in that, if the buyer knows what he is buying. But if he thinks it is some mysterious engine-era weapon, then the gap between expectation and reality widens. The real risk is not competitive but evidentiary. A promotional text asserts an evaluation without any proof, and behind that claim there is no engine, no sample game, no statistic. The second risk is predictability: over-reliance on one sideline eventually makes a player predictable. Once this line becomes popular, White will prepare his counter, and the sideline's shelf life shortens. Judged technically, 9...a5 is strategically coherent. It pursues ...a4 and ...b5 ideas to disrupt the queenside, and gives Black a plan-based game. For a player who wants understanding instead of memorisation, it is reasonable. But whether it is objectively stronger than the main line 9...Nh5 is unproven at this moment. It is probably slightly weaker, yet easier to play in human hands. My personal experience says that at club level such sidelines often yield more than the main line — because the opponent is prepared for the main line, not for the sideline. At the 2026 Premier Division Chess League I saw fourteen guest signings in a nineteen-day signing window; around then I heard that many club players were looking for low-memorisation sidelines instead of memory-based main lines. The reason is simple — less time, more preparation. But a subtle truth hides here. A sideline that becomes popular for practical reasons eventually becomes a target of theory. What is neglected today as 9...a5 will one day fill the databases, and White will build his antidote. That is, the antidote itself has a shelf life. In the training-materials market nobody wants to admit this, because admitting it reduces sales. Now let me close the notebook. The true value of this DVD lies not in objective proof but in instructional utility. It is a good example — how the memory-versus-understanding trade works, how the choice between a main line and a practical sideline changes a player's style of preparation. That lesson is valuable, provided the reader does not mistake marketing language for theory. But my objection is to the ethics of the market. When a product claims equal chances and danger for White without proof, the buyer can be misled. A player who builds his preparation on this advertisement may invest in a line that is in fact slightly weaker. The responsibility here lies with the seller, not the buyer — because the buyer has no time to verify. In the end, my question returns to that boy at Purana Paltan. He had memorised seven pages of 9...Nh5. If someone had told him there was a sideline on the exact opposite side of his seven pages, one that would free him from memorisation, he might have been glad. But did he know that the equal-chances claim of that sideline had not been verified? Probably not. And this not-knowing is the biggest problem. I am not condemning this product. The opening-theory market is mature, and the re-release of sidelines is a normal part of it. But in this market I want a ledger — what proof lies behind which claim. Without an engine evaluation, without a sample game, without statistics, equal chances is just a sentence. And my job as a beat keeper is to stand that sentence in front of the engine. Looking ahead, I will watch four signals. First, what the current engine says about 9...a5, and whether it is weaker than 9...Nh5. Second, whether elite players use this sideline against the Bayonet — if they do, it will gain standing. Third, when White's counter-antidote arrives, because it will. Fourth, what the true identity of the ChessMom title is — whether this mismatch is ever resolved. Until these four questions are answered, I will keep this DVD as a possible sideline pointer, not as proven theory. To the boy at Purana Paltan I would give exactly this advice — before writing in the notebook, sit in front of the engine, then decide. The notebook says one thing, the tape says another; and in chess the tape has the last word. Round three is where this story stopped, not where it ended — and from there another lesson emerges: a theory coming to market and being true are not the same. I have seen many theory products arrive in glossy marketing language, then slowly and silently fade in the databases. 9...a5 may join that list, or it may stay. What decides the difference is evidence, not ornament. And producing that evidence takes time — not nineteen days, but a few years. The last line in my ledger is this: the value of an antidote lies not in its novelty but in its durability. A sideline that survives the test remains; one that does not returns to the advertising page. The future of 9...a5 against the Bayonet Attack is not yet written — it will be written by the engine, the database, and that boy sitting beside the board, with seven pages of memorisation in his hand.