9...a5 in the King's Indian: Auditing a Repertoire DVD Against the Bayonet Attack

The first thing that shows is the gap between the packaging and the contents. The box reads "ChessMom returns: Supporting mothers on and off the board." A buyer who reads that title expects a social-welfare story or a training initiative about mothers. Inside, he finds something entirely different: a repertoire DVD for Black against White's Bayonet Attack in the King's Indian Defense Mar del Plata, whose central proposal is a single move — 9...a5. The mismatch between title and content is itself a piece of information, and for an auditor it is the first warning. When the name on the cover and the move inside do not describe the same thing, the question is not one of story but of provenance: whose source is this, when was it made, and where are the numbers attached to it?

Context: the accounting behind one move

The King's Indian Defense (1.d4 Nf6 2.c4 g6 3.Nc3 Bg7) is a hypermodern defense. Black gives up the center at first, then strikes it with ...e5 while keeping ...Bg7 for long-term pressure. Its classical branch runs 7...Nc6 — the Mar del Plata Variation. Both sides build attacks on opposite wings: White on the kingside, Black on the queenside. That asymmetry is the system's beauty, and also its burden. Watching these lines for years has made one thing plain to me: in the classical King's Indian fight, the result usually goes to the side that starts its own attack first, and the accounting of the two wings' speed is nearly everything here.

White's most popular modern weapon is 9.b4, the so-called Bayonet Attack. It blocks Black's queenside plans early, questions the occupation of c5, and forces Black toward an answer that is not easy to memorize. Black's main reply is 9...Nh5 — it opens the position and produces forced, tactical play. Here is the problem. This line carries a huge memorization load, and the weight of computer analysis is heaviest. For a player with no time to hold engine lines, it is a steady erosion.

The DVD's sales pitch is simple: this forced path can be avoided with 9...a5. The move claims space on the queenside, keeps the plan of ...a4 and ...b5, and — so the claim goes — produces healthy positions with "very few concrete lines." Understanding in place of memorization. That is the product's core promise, and also its main risk.

Core analysis: denominator first, story later

The question is not whether 9...a5 is a good move. The question is: how many lines must be memorized, how much time is saved, and what is given up in return? In the main line 9...Nh5, Black faces fresh engine corrections almost every month, because the Bayonet is a fashionable system and every branch of it is frequently tested. The real market for a repertoire product sits exactly here — club-to-IM level players who lose precious time at the memorization table the night before a tournament.

From Moscow, one comparison is obvious to me. Here, the state and the clubs treat chess as infrastructure — not mandatory, but continuous. In Dhaka's reality, a single move often depends on one patron or one club. That difference feeds straight into the market for a product like 9...a5: where the training structure is weak, "less memorization, more understanding" is the most saleable promise of all.

But the hard part of the accounting is here. Not one of the fourteen information points in the analysis carries a number. No average centipawn loss, no engine evaluation, no win-draw-loss ratio from any database, no sample games. Only qualitative claims. Yet a repertoire product's receipt is incomplete without four things: the move's engine evaluation, its results in a current database, a comparison with the rival line, and the sample size. Since I published my first public xG model, my rule has been one thing — no claim without a number, and no number without its source. Here, the source is missing.

When a product says "objectively the chances are equal, but things can quickly become dangerous for White if Black knows the plans," it is blending two different things — an objective evaluation and a practical edge. The first needs evidence; the second needs only an unprepared opponent. This blend is the oldest device in repertoire marketing. A transfer rumor is a story, a transfer fee is a number — and here too I wait for the number.

The value of a practical sideline can be measured in three ratios: the number of lines to memorize, the time spent per line, and the success rate of that preparation in competition. A DVD can supply the first two; evidence for the third comes only from games — and the game sample here is zero. When empty stadiums gave us a control group we never would have dared to create, the lesson was clear: no claim survives without a sample, whether it is football or chess.

The null result nobody wants to write

A null result belongs on the record here, because it is the most frequently skipped. 9...a5 is not a new move. It is a known, established sideline in the King's Indian Bayonet — an old idea that fights for queenside space and keeps ...a4/...b5. The DVD is probably selling existing theory in new wrapping. If it claimed no novelty, there would be no problem; the problem is the attempt to make it look new. The DVD format is itself another signal: in the age of subscription course platforms, a DVD is a legacy channel under structural pressure. The difference between a catalog re-release and fresh analysis is something the buyer deserves to know.

Contrarian view: correlation is not cause

The weakest sentence in the advertisement is this: "computers often do not know how to handle the arising complex strategic positions." In the engine era, that claim is anachronistic and overstated. Modern engines handle the closed, strategic King's Indian positions well. It is not a technical claim but rhetoric — and a product that leans on rhetoric instead of evidence has a promise of the same weight.

There is another gap: confusing correlation with cause. "If Black knows the plans, it is dangerous for White" is probably true, but the cause is not the objective strength of the move — it is the opponent's lack of preparation. A sideline that becomes popular becomes a target itself. Then White's counter-preparation arrives, and the sideline's shelf life shortens. It is worth stating what this information does not contain: no player's name, no tournament, no rating trend. So pulling anyone's future, or "who the next grandmaster will be," from it would be baseless. A model is a receipt, not an oracle.

Forward signals

Three things to watch. One, the current engine's evaluation of 9...a5 — if it scores clearly worse than 9...Nh5, the product's central claim collapses. Two, its adoption at elite level — if a grandmaster plays it against the Bayonet, the sideline gains legitimacy. Three, White's counter-theory — if a clear White advantage is published, the sideline's shelf life shortens. When the numbers arrive, the story changes. Until then, this DVD is a question, not an answer.