The 9...a5 Move and the Price of Surprise: A Look at a King's Indian Opening DVD

On a Thursday evening at a small chess club on Phu Loi Street in Thu Dau Mot, a player rated around 2100 Elo, whom I will call H., opened the opening DVD he had just bought online. He set up the board, rewound the introduction for the third time, and wrote two characters on a piece of paper: “9...a5”. Ten minutes later, H. sat down at an online board and chose the King’s Indian Defense position he had just studied. His opponent played the Bayonet Attack with 9.b4. H. replied 9...a5. The other side thought for about forty seconds, then pushed 10.b5. H. hesitated. He could not remember the next move, so he had to calculate on his own, and twenty moves later the position slipped out of his hands like a stone off the edge of a table. The game ended, but the applause still echoed in my memory — here it was the click of a “rematch” button from a player who had just realized he had bought surprise, not understanding.

That story is not H.’s alone. It is the story of a product being sold as an “antidote” for King’s Indian players tired of being out-prepared. The product is an opening DVD with no author, no publication date, and no product ID in the promotional material I have. The marketing revolves around an appealing idea: instead of memorizing the main lines of the Bayonet Attack, play 9...a5, a rare move that forces the opponent to think for themselves. The blurb goes further: computers do not understand these positions, and objectively the chances are said to be equal.

I spent several evenings rereading that blurb, comparing it with what I know about the King’s Indian Defense, the Bayonet Attack, and the way the computer era has changed opening preparation. Based on my experience following games, from amateur events in Binh Duong to high-rated online games, I see a large gap between the marketing language and the reality on the board. The gap is not in the move 9...a5. The move is real. The gap is in how it is sold.

The key point is that 9...a5 does not create a new position; it shifts the cost of preparation from memory to judgment, and the buyer pays with calculation time.

To understand why that pitch appeals to club players, it helps to place it in the flow of the King’s Indian Defense. The opening has a famous branch called the Mar del Plata, where Black allows White to take space in the centre and then counterattacks with waves on the kingside. White usually plays 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. Then the Bayonet Attack appears with 9.b4. White pushes the queenside pawn, opening the way for a broad space plan: b5, Ba3, Nd2, Re1, and then either opening the queenside or holding the centre.

The main line of the Bayonet is 9...Nh5. Black puts the knight on the rim, preparing ...f5, ...f4, ...g5, ...Ng6, ...Rf7, the symbolic moves of the Mar del Plata. This is dense theory, where professionals may remember dozens or even hundreds of moves, and where a small move-order error can lead to disaster. That is why a move like 9...a5 has great appeal for amateurs. It says: you do not need to remember everything. You only need to understand the idea.

But the promotional material I have contains a notable documentation gap. It stops the move sequence at 7.0-0 and jumps straight to 9.b4, omitting 7...Nc6 and 8.d5 Ne7. For anyone familiar with the King’s Indian, those two moves are the necessary bridge. Without them, the Bayonet Attack cannot appear. This is not a chess error but a storytelling error: the text was written to persuade, not for a buyer who intends to sit down and execute the line. A serious buyer will notice the gap at once. A buyer tired of theory may skip it, because what they want to hear is “you do not need to memorize anymore”.

The move 9...a5 has its own logic. It attacks the b4 pawn and forces White to decide immediately on the queenside. White can play b5, push the pawn further and keep space. White can also trade with bxa5, opening the a-file for Black and giving Black an open file for counterplay. The move turns the game from forced sequences into a positional struggle in which both sides must constantly assess pawn structure, open files, weak squares, and development rhythm. Structurally, the blurb is not wrong. It simply misnames the nature of the benefit.

The real benefit of 9...a5 is variance reduction in preparation cost. The player does not have to remember a long main line; instead, they must understand a layer of ideas. For a player with time, that is a practical advantage. For a player with little time, it can be a trap: they think they are buying simplicity, but they are buying a different kind of complexity. The main line 9...Nh5 demands memory. 9...a5 demands judgment. The two do not replace each other for free.

The blurb makes a stronger claim: computers do not understand these positions. I read that sentence and remembered evenings analysing with a coach in Ho Chi Minh City, who once told me that every “computers do not understand” argument has an expiry date. That date came sooner than many expected. Since Stockfish 12 appeared in 2026 and brought NNUE into evaluation, followed by the maturation of Leela Chess Zero-style engines, closed, structure-rich positions with few forcing lines have been read much better than before. Engines can still misjudge deeply strategic positions, but the gap implied by the blurb is no longer true at that level.

The argument that survives the NNUE era is narrower and different. In 9...a5 positions there are fewer forcing lines to memorize. The human-versus-engine gap is therefore a memory gap, not an understanding gap. The buyer’s opponent can still engine-check the position in fifteen minutes. They can still find reasonable moves. They can still prepare a plan against 9...a5 if they know it is coming. Surprise has a shelf life. It is not a permanent wall.

This is the biggest technical weakness of the entire promotional text: it supplies no quantitative data. There is no engine evaluation, no ACPL, no game count, no database statistics, no complete sample line beyond a single move. For an opening product, that absence is diagnostic. It shows the text was written as a sales pitch, not as a technical report. The buyer has the right to ask: how many games has 9...a5 been tested in? At what rating level? With what results? Those questions go unanswered.

The claim that “objectively the chances are equal” sits in the same fog. In Mar del Plata structures, White often has durable space and a queenside majority plan, while Black plays for kingside initiative. That is a high-variance balance, not a symmetric equality. To say the chances are equal without an evaluation, without a database source, and without a reference game is to present an unsupported judgment as fact. It may be roughly true at engine depth, but it is stated as truth. For a careful reader, the distance between “possibly true” and “proven” is the distance between advertising and analysis.

There is another issue the blurb never touches: the asymmetric payoff of a rare line. A rare move benefits the side that has studied it only until the opponent’s preparation catches up. The half-life of surprise is inversely proportional to the move’s popularity. If 9...a5 appears in major events, coaches will put it in files. If it remains a club-level rarity, it may last longer. But the blurb never quantifies this. It sells surprise as a fixed asset, when in reality it is a depreciating one.

I tried to put myself in the buyer’s position. A 2100 player with a day job, three or four hours a week for chess, regularly facing opponents prepared for the Bayonet. For that player, the DVD can be useful. It offers an escape from the 9...Nh5 theory dump, a way of saying: if you cannot remember it all, play a position you can calculate. But if that player believes 9...a5 will give an objective advantage against a stronger opponent, they will be disappointed. The move does not turn an average player into an expert. It only changes the kind of question the player must answer.

For players below 2026, 9...a5 may be useful at a medium-high level, simply because opponents rarely prepare the Bayonet deeply. Between 2026 and 2400, practical utility peaks: opponents do prepare, but not always to the point of having every sideline in their files. Above 2400, that utility falls sharply. Opponents and their seconds will have the move in their preparation, and the main line 9...Nh5 reasserts itself. The blurb does not say this, but the buyer should say it to themselves.

There is another notable detail: the product names no player. There is no titled author, no grandmaster testimonial, no sample game from anyone. For a chess instructional product, this is a major credibility omission. The genre norm is author name, title, and a few sample games so the buyer can judge style. Without them, the buyer cannot answer the most important question: does this approach suit me? An opening product can be technically sound and still not fit a player, because each player feels positions differently. With no author and no sample games, the buyer can only trust the pitch.

I remember an afternoon at the Binh Duong chess club, when an older player set up a King’s Indian position on a wooden board. He did not use a computer. He placed the pieces slowly and said: “This opening is like holding a door. You do not need to push it open; you only need to know when to open it.” That sentence made me think of 9...a5. The move does not open the door to victory. It only changes the lock. The player still has to learn how to open it.

The board has pieces, and it also has the calluses of a life. Those calluses are hundreds of hours of analysis, games lost to a forgotten move order, nights rewinding a DVD segment without understanding why one still loses. When there is no audience, chess returns to its own breathing. And in that breathing, the player hears the clearest question: am I buying understanding, or only a feeling of safety?

Age does not extinguish love for the board; it only changes its colour. Younger players may memorize faster, but older players often understand non-forcing positions more deeply. For them, 9...a5 can be a gift: an entry into the King’s Indian that does not demand extraordinary memory. But the gift is only valuable if they accept investing time in understanding pawn structure, open files, and rhythm. Otherwise, it becomes a move abandoned after a few games.

Technically, there is a practical risk the blurb does not mention: strategy-first positions are more time-hungry than memorized forcing lines. In rapid or blitz, the 9...a5 player must keep making structural decisions, while the opponent may play by reflex if they know the main line. This does not mean 9...a5 is weak. It means its advantage depends on the time control. A product advertised for everyone without distinguishing classical, rapid, and blitz is incomplete as instruction.

It should also be said clearly: White’s natural replies to 9...a5, such as b5, Ba3, and Nd2, are not discussed in the blurb. This is a serious technical omission. A serious buyer needs to know what the opponent will do, not only what they themselves will do. If the blurb does not present the refutation front, the buyer enters the game with half the picture. They may win a few games through surprise, then lose repeatedly once opponents begin preparing. At that point, they will ask whether the fault lies in the move or in the seller.

I do not think 9...a5 is a bad move. It is a reasonable option for players who want to reduce the theory burden and are willing to play positional chess. But I do not think it is an “antidote” in the way it is sold. In chess, there is no antidote to preparation. There are only different ways of allocating time. A player can study 9...Nh5 and remember more, or choose 9...a5 and calculate more. Both have a price. The question is which price fits.

Based on my experience following games, the most successful opening products are not the ones that promise the most, but the ones most honest about the price. A good DVD says: this is what you gain, this is what you lose, this is what the opponent can do. A DVD that sells surprise without mentioning its expiry is like selling a ticket valid for one train only.

There is one point I want to leave for anyone considering this product. If your goal is to escape the feeling of being overwhelmed by Bayonet theory, 9...a5 can be a useful entry. If your goal is to find an objective advantage against strong opponents, be careful. The move does not create that advantage. It creates a different position, where you must take responsibility for your decisions. And responsibility, in chess as in life, is never sold complete.

The game ended, but the applause still echoed in my memory. At the Thu Dau Mot club, H. bought another book on pawn structure. He told me he would still play 9...a5, but this time he would study White’s replies too. That is the right way to read an opening product: not as a promise of victory, but as a map with the turns marked. The map may lead to a win or a loss. What matters is that the person holding it knows where they are.

In the modern chess world, where engines have read more positions than ever, human value does not lie in hiding a move from an engine. It lies in understanding why the move exists, when it matters, and when it is only a way of postponing harder learning. A DVD can teach a move in fifteen minutes. To understand it, a player needs more: quiet evenings, unseen losses, and a little honesty with oneself.

Perhaps the most lasting lesson from this story is a question with no universal answer: when you sit before a rare position, are you looking for an exit or an entrance? If it is an exit, remember that every exit has a guard. If it is an entrance, bring enough time to walk the whole road. The board does not promise ease. It only promises that every move leaves a trace, and the player who dares to look at that trace will learn more than one opening line.