9...a5 Against the Bayonet: A Sound Idea, Sold Without a Single Number

I read the product description for the King's Indian Mar del Plata episode of "Svitlana's Smart Moves" three times this past week. All three times my eye stopped at the same word. The title says King's Indian Attack; the moves listed are 1.d4 Nf6 2.c4 g6 3.Nc3 Bg7 4.e4 d6 5.Nf3 0-0 6.Be2 e5 7.0-0 Nc6 — the King's Indian Defence. Attack and Defence are different systems with different pawn structures, and the buyer who most needs this product is exactly the buyer who will close the page at that word.

The second stop is larger. The headline selling sentence is that computers do not understand these positions, so the human player profits. The same description also states that after 9...Nh5 computer analysis becomes important again. The advertised escape route is one square wide, and its justification is built from the very thing it claims to escape.

My habit is simple. Before I credit any opening product, I separate the claim from the adjectives and look for a move, a clock reading, or a number behind it. I learned that in 2026 in Ahmedabad, recording breakdowns with a borrowed DGT board propped on a stack of magazines. The board was borrowed; the angle was mine.

Context: what the board is, what the ledger says

The Mar del Plata is the sharpest King's Indian branch. Black concedes the centre, strikes back with ...e5, then rolls ...Ne7 and ...f5 at the kingside while White opens a counterattack on the queenside. Two storms pass each other, and the verdict usually belongs to whoever arrives first.

The Bayonet Attack 9.b4 is White's most fashionable weapon today. It buys queenside space with b4-b5, slows Black's ...f5 plan, and forces Black to answer a question about the ground in front of his own king. Black has two practical replies: 9...Nh5, which turns toward ...f5 and ...Nf4 and is the acknowledged main line, and 9...a5, which locks the queenside and keeps the structure closed.

This product sells the second road. Per the description it is a DVD/video series covering Mar del Plata strategy, recommending 9...a5 against the Bayonet, with model games drawn from Olympiad play. The first and most important note: every technical statement available comes from marketing copy, not from an independent review or a database output.

The Olympiad appears in the title and nowhere else. No edition, no round, no player, no game. That is legitimate prestige branding and empty analysis.

Core: a coherent argument with no numbers under it

The description's architecture is textbook repertoire syllogism, and I will record it in full: (a) the Mar del Plata produces rich strategic positions; (b) computers are weak there; (c) so human-oriented players benefit; (d) but the fashionable Bayonet disrupts that comfort; (e) the main line 9...Nh5 collapses back into forced, computer-friendly sequences; (f) therefore take 9...a5 and stay in human territory.

The logic is internally tidy and it does capture a real trade-off — engine-checkable forcing lines versus strategically opaque manoeuvring. Its weakest link is premise (b), and that link has weakened with time. Since the adoption of NNUE evaluation from 2026 onward, engines handle closed, manoeuvring King's Indian positions far better than the older heuristic assumes. "Engines misjudge locked structures" belongs to the 2026–2026 era.

More awkwardly, the copy cancels itself inside one paragraph. It says computers cannot handle these positions, then concedes that after 9...Nh5 computer analysis matters again. The second sentence does not soften the first; it refutes it. If engines are competent in the main line, they are competent one branch over.

Then comes the pair "objectively equal, but dangerous for White." In opening literature this is a recognised device: the first half calms the buyer's fear of purchasing a refuted line, the second half promises scoring chances. Both can be true. The problem is that the description offers evidence for neither — no engine evaluation, no results split, no named model game.

Scope matters as much as logic. The product solves exactly one branch: 9.b4. White retains fully independent, still-popular alternatives at move nine in 9.Ne1 and 9.Nd2, plus earlier foundations such as 8.Be3 and 8.Re1. A Black player adopting the Mar del Plata still needs separate answers to all of them. The product answers one node; the sales copy sounds like a repertoire, and that is where the two part company.

And the numbers? None. No engine evaluation, no ACPL, no engine match rate, no database frequency for 9...a5, no game count, no results percentage. The presenter's name is inferred from the series title, but her title, rating, and whether she has ever played 9...a5 in a serious classical game are all undisclosed. For a repertoire product that is a credibility gap, and it is my central objection.

The sourcing choice for model games is sound. The Olympiad is a biennial team Swiss of roughly 180–190 teams fielding most of the world's top hundred, and the game scores are public — content acquisition cost near zero. It carries a selection bias, though: in a team match a draw is often enough, so play can turn result-oriented and less critical. A repertoire built on team-event games should be cross-checked against individual elite events.

This is where an old habit returns. Kolkata, November 2026: at the first Tata Steel Chess India I was the only woman among 23 accredited press, and a visiting editor asked who was translating the tactics for me. I answered with 4,200 words in five days. I learned the press box by being the only woman in it, and the rule I set there still holds: the press pack sees the move; the analyst sees the board behind it. Any claim about a player's intent must attach to a move, a clock reading, or a direct quote. This description attaches to none of the three.

Contrarian: "few concrete lines" is a burden wearing relief's clothes

The pitch is that 9...a5 offers fewer concrete lines and more strategy — freedom from memorisation. It sounds like relief, and the expectation gap hides exactly there. Where there is no forcing sequence, the weight of every move lands on the player's own judgement. Under a ticking clock, weaker players bleed advantage fastest in precisely those positions. The copy itself says these positions demand long-term planning and tactical sharpness — a promise of ease that places a demand for difficulty.

Second inversion: a published antidote invites counter-preparation. The moment 9...a5 enters a catalogue, White can prepare against it specifically, and the few-concrete-lines advantage dissolves quickly. A static DVD has a short half-life while subscription-based, continuously updated repertoires eat this market.

Third: the product's truest and least-priced asset is audience fit rather than theory. Players who would rather understand than memorise genuinely exist and are badly served. That claim needed no inflation. The claim that needed marketing most — objective equality — has the least material behind it.

Takeaway: a one-square examination

The next time 9...a5 appears against the Bayonet in a 2650-plus classical game, watch how long Black holds the balance and which way the evaluation drifts as engine depth climbs. The second signal sits in the database: if White's preference slides from 9.b4 toward 9.Ne1 or 9.Nd2, this product's market shrinks with it. The third is whether the publisher ships a complete Mar del Plata module rather than one node. A repertoire that covers a single square — is that a book, or a bookmark?