The 9...a5 Move Against the Bayonet Attack: A Clean Fix or Opening Marketing?

Moscow winter, the temperature outside drops to minus fifteen. I open an opening study package just received from a publisher specializing in chess DVDs, and right on the cover is an advertisement for the move 9...a5 as an "antidote" to the Bayonet Attack. The bold text reads: "sound positions, equal game, very few concrete lines". I have sat at the board for more than fifty years, enough to know that whenever a product calls itself a "clean fix", that is exactly the moment to check it myself. From the flank corridor, I see the whole game — and this time, that flank corridor is the queenside of the board. The game begins with the King's Indian Defense, Classical system: 1.d4 Nf6 2.c4 g6 3.Nc3 Bg7 4.e4 d6 5.Nf3 0-0 6.Be2 e5 7.0-0 Nc6. This is the Mar del Plata variation, a name tied to the 2026 tournament in Argentina, where Black lets White take the center and then strikes back with ...e5 and ...f5. White continues 8.d5 Ne7, shifting forces to the queenside. Then comes 9.b4 — the Bayonet Attack, White's most ambitious try, opening the plan to expand on the queenside. For decades, Black's mainstream answer has been 9...Nh5, bringing the knight into play, targeting the center and preparing ...f5. That is the main theoretical highway, where lines are forced and computer analysis is decisive. The product in my hand proposes another route: 9...a5. Instead of developing the knight, Black strikes directly at the b4-pawn just advanced, forcing White to decide immediately about the queenside structure. Technically, this is not a new invention. 9...a5 is a sideline known for a long time, once used as a direct blow against White's queenside. What stands out is how the seller positions it: "strategy, not tactics", "very few concrete lines", "objectively equal chances". This is the language of a playable equalizing sideline, not a theoretical refutation. It should be read as "a practical system based on understanding", not "a forced advantage". The product's real value lies in its anti-memorization argument. The author contrasts 9...a5 — few forced lines — with 9...Nh5, where the position opens up, lines become forced, and "computer analysis becomes important again". For a player who does not want to memorize hundreds of moves, this is an honest selling point and the biggest genuine benefit. People watch the pieces move. I watch the whole structure shift — and here, Black's whole structure shifts slowly, deliberately, relying on long-term plans rather than snap calculation. But there is one point where I must stop. The claim that "computers don't know how to handle these positions" is a classic marketing trope of opening DVDs, and it is analytically dubious. Modern engines handle Mar del Plata positions well. The author himself concedes that after 9...Nh5, the role of the computer "returns to importance" — which implicitly admits engines evaluate these structures well. When a seller says both "computers don't understand" and "computers matter again", the first is a slogan and the second is the technical truth. Here is where I must speak plainly: every favorable claim — "sound", "equal", "dangerous for White if Black knows what to do" — comes from the seller, not from independent data. There is no win rate, no game sample, no engine match rate. My first article got pelted with stones. Data never takes offense. In 2026, when my analysis of RB Leipzig's gegenpressing was called "conservative" by the Russian online community, I did not argue. I spent six weeks reviewing footage, counting 412 failed pressing situations. Here too: before trusting 9...a5, one must verify it against a game database. There is one more risk buyers rarely notice. The 9...a5 line has few forced moves, meaning low risk of falling into prepared traps, but also little margin for error if the player misjudges the strategic plans. The author himself concedes that "if Black knows what to do, things can quickly become dangerous for White". The reward depends on the buyer truly absorbing the plans, not just memorizing the move list. For a memorizer, the promise of saving effort is precisely the weakness in real play. On top of that, slow strategic plans are easily punished in blitz and rapid, where time does not allow deep thought. The system does not lie, but it can only be heard when the data is thick enough. Here the data is not thick enough — the only source is the product's own advertising. A wise King's Indian player will keep 9...a5 as a second weapon, alongside the familiar 9...Nh5, and re-check the line periodically as theory shifts. The difference between a useful equalizing sideline and an inflated "clean fix" is not on the DVD cover. It is on the board, and it only shows when one sits long enough to check.