9...a5 against the Bayonet: an 'antidote' with no verifiable data

On the product page, a neat promise: a way to meet the Bayonet Attack with "very few concrete lines", aimed at players who prefer to think for themselves rather than memorize. The move on sale is 9...a5 in the King's Indian, Mar del Plata system. I finished reading it and the first thing I did was not open a board. I opened a database. The first question was not whether the move is good or bad. The question was: which games, who played them, what time control, and what were the win and draw rates. The page answered none of it. People call that a shock. I call it data that has not been read. King's Indian Defense (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) is the classic hypermodern opening: Black concedes the centre early and counterattacks later. The Mar del Plata system — with ...Nc6 and ...e5, roughly ECO E97–E99 — is its sharpest branch, where both sides attack on opposite wings. White usually chooses the Bayonet Attack 9.b4 to gain queenside space. Black's main reply is 9...Nh5. This product sells a different move: 9...a5. It must be said plainly: 9...a5 is not a novelty. It is a known branch, and a secondary one. It forces White to make a decision about the b4-pawn and steers the game towards a tighter structure with fewer forcing lines. The product does not claim a theoretical edge for Black; it claims the chances are equal. The value being sold lies in practicality: less memorization, fewer variations to recall, more room for positional thinking. One sourcing detail has to be stated before going further. The original title of the text is "Samarkand R2 (open): Despite close calls, all top teams grab wins" — a team-event round report. The entire body concerns the opening DVD. Two unrelated texts have been spliced together. For a data reader, that is not a small detail. When a source contradicts itself at headline level, every claim beneath it has to be re-verified from scratch. I reconstructed the sales pitch in three layers. The first layer is the technical claim: after 9...a5 the position contains "very few concrete lines". That is a claim about the character of the game, not about an advantage. To test it I need exactly three kinds of data: a sample of games, win-draw-loss rates, and the average centipawn loss (ACPL) of both sides against the engine's top choice. None of the three appears in the text. The second layer is the engine claim: 9...Nh5 "opens the position, forces the lines, and makes computer analysis important again", while 9...a5 leads to "sound positions with very few concrete lines". That sentence sounds familiar. It is the language of the pre-AlphaZero era. Today's neural-network engines handle long-term King's Indian positions far better than the sentence implies. A move does not leave an engine helpless; it merely makes the engine score the position differently. An engine score does not replace emotion; it explains why the heart races. The third layer is the psychological claim: "if Black knows what to do, things might quickly become dangerous for White". That is standard sales copy. It is true in the obvious sense — good preparation helps — but it cannot be verified with data, because it depends entirely on the opponent's level of preparation. The number is an ascetic discipline: you have to give up what is easy before you can see what is true. Placing 9...a5 alongside the leading theoretical trends shows its real position. At elite level, the engine era has pushed choice towards low theoretical risk: Grünfeld, Nimzo-Indian, Italian. The King's Indian Mar del Plata is high theoretical risk — it concedes space and invites sharp play. That is why it survives at the top mainly as a surprise weapon rather than a daily choice. Within that framework, 9...a5 is a secondary branch of an already secondary opening. Its value is not in overturning theory but in dragging the opponent out of familiar preparation. The product's market also deserves a straight look. Fritztrainer-style ChessBase opening products sit alongside free databases and engines. They cannot win on raw variations, because anyone can look those up. They have to win on editorial structure and narration. That is why the "few concrete lines" pitch matters so much — it is the differentiator against the free tools themselves, not a technical fact. And this is where I am most cautious. In 37 years of watching this industry, I have seen far too many "antidotes" survive exactly one theoretical cycle. A promoted sideline gets dissected by the White side, and the response usually arrives within months. What worries me is not the move 9...a5. It is the way the text presents itself. Two genuinely independent sources must have different origins. Here I have one document, and that document contradicts its own headline. If all three "pieces of evidence" flow from a single product page, they are not three sources — they are one source counted three times. My three-source discipline exists precisely to stop this kind of error. The claim of "very few concrete lines" is also likely overstated. The Mar del Plata system remains sharp by nature. No branch removes calculation from chess; it only makes calculation less dependent on memory. The product's real value probably lies at club and international-master level, not at the level of leading grandmasters. That may well be a good market — just not the market the advertising implies. The absolute tone ("things might quickly become dangerous for White") is a sign of expectation inflation. When a product promises results without offering a single sample game, I read the promise as advertising, not as a conclusion. For a buyer, the biggest risk is not the money. The risk is study time dissipated on a branch that a well-prepared opponent can still neutralize. I will track four signals over the coming months: whether 9...a5 appears in classical games at the 2700+ level — the only test that carries weight; whether the frequency of the Bayonet Attack 9.b4 holds, since the product's relevance window depends on it; the author's identity and their results in the Mar del Plata itself; and whether a White-side response emerges within one theoretical cycle. The opening-theory market is a place where people pay for variations that have not been verified. That is not wrong in itself — but buyers should know whether they are paying for editorial structure or for a confirmed fact. The question I leave behind is simple: if the move really makes White's position dangerous so quickly, why is there not a single game cited to prove it?