9...a5 and the Battle for b4: Inside a King's Indian Opening DVD

A coffee shop on the corner of Nguyen Chi Thanh Street in Da Nang closes at eleven at night. Last Saturday, a fourteen-year-old boy sat across from me, pushed his b-pawn to b4, and looked up, waiting. He did not know he had just touched one of the longest chapters in modern chess theory.

Ten minutes later I opened my phone and scrolled back to an email a colleague in Europe had sent a few days earlier. The summary was short: a new opening DVD, King's Indian Defence, Mar del Plata variation, with the promise that Black's ninth move -- a5 instead of Nh5 -- would solve the headache known as the Bayonet Attack.

I read it twice. Then I thought about Warholm.

Three years ago, around this time of year, I kept replaying Karsten Warholm's 46.70-second finish at the Tokyo National Stadium. Twenty times. I counted every stride between the hurdles the way a gamer counts frames. At fifty, I still do that. Pulling back the curtain on speed, I met a whole generation running; this time, opening the board again after 9.b4, I met a whole generation calculating.

What I realised is that an a5 in a DVD selling for a few dozen euros has the same nature as a stride between two hurdles. Both are decisions hidden behind an outcome that looks very simple. People talk about speed, but what I find is time.

CONTEXT: A SYSTEM BUILT ON CONCESSION

The King's Indian Defence is a designed paradox. Black plays g6, puts a bishop on g7, lets White occupy the entire centre with pawns on d4 and e4, and then simply waits. In classical chess, conceding the centre like that is considered suicide. In the King's Indian, it is the whole plan: let your opponent build a big centre, then tear it down from the flanks.

The Mar del Plata is the sharpest version of that idea. Black develops the knight to c6, pushes the e-pawn to e5, and ignores White's freezing of the centre with d5. The game splits into two parallel races: White advances queenside pawns, Black advances kingside pawns, and whoever arrives first wins. That is why the line carries the name of an Argentine seaside city where it was refined in the great tournaments of the last century -- and why it has never disappeared from top-level boards. Its ECO code sits roughly between E97 and E99.

The problem appears on White's ninth move. Instead of continuing with slow pawn advances, White can play 9.b4, known as the Bayonet Attack. The idea is blunt: thrust the pawn to b4 immediately, without asking permission, and force Black to answer before completing the kingside plan. The Bayonet is not trying to win a decisive advantage. It is trying to win time.

Over the past two decades, the Bayonet has moved from a surprise weapon to a habit. Young players use it because it is forcing: once b4 appears, Black is pushed into a small number of heavily analysed lines. For someone with a good memory, that is paradise. For someone who wants to sit and calculate, it is a prison.

And that is precisely the crack the product in my hand wants to walk through.

The Vietnamese story is not outside this current. When I used to organise amateur events in Da Nang, young players kept asking me the same question: how many lines do we need to memorise before it is enough. I never had a tidy answer. But I always remembered that Le Quang Liem, Vietnam's number one for many years, never became famous for a vast opening database. He became famous for games in which the opening ended and the game actually began.

WHAT IS INSIDE THE MOVE 9...a5

This product sells a single idea, and it does not hide it. After 9.b4, instead of the familiar 9...Nh5, Black plays 9...a5.

The move looks so modest that it is easy to miss. Black does not attack the king, does not open a file, does not threaten anything immediately. Black simply declares: this b4 square has a price. The a5 pawn touches the b4 pawn, forcing White to decide right now -- trade, push on, or keep the tension and accept a locked structure.

In practice, White often answers with Ba3, placing the bishop on the long diagonal, and Black can trade on b4 and open the a-file for a rook. The resulting structure is a closed position where the pieces no longer charge at each other but stare at one another across a fence of pawns.

This is the crux that the professional analysis calls a change in the character of the game. With 9...Nh5, Black commits. The knight jumps to h5, threatens to leap into f4, forces White to calculate move by move, and punishes every small deviation with a direct attack on the king. With 9...a5, Black retreats into a different fight: slower, more closed and -- according to the advertising -- requiring fewer forced lines.

That is the psychological appeal. The value of 9...a5 does not lie in being stronger than 9...Nh5, but in shifting the game from a memory test to a patience test. For a certain kind of player, that is a more attractive offer than any engine analysis.

One thing the promotional material does not say must be stated clearly: 9...a5 is a known branch. It is not a new invention. It has appeared in databases for a long time and has been used by strong players as a reserve option, a change of air. This product is not selling a new move. It is selling a presentation.

9...Nh5: THE MAIN LINE AND THE PRICE OF MEMORISING

To understand why a secondary branch has a place at all, you have to understand why the main line is so tiring.

After 9.b4, the move 9...Nh5 is the most played reply. The black knight jumps to the rim, preparing to enter f4, where it will stand in the middle of White's formation and create direct pressure on the king. White usually must respond with Re1 or g3, and the game explodes.

The nature of these lines is forcing. If either side plays one tempo off, the position collapses immediately. That means both sides must remember. Not a few moves, but an entire tree of variations with dozens of branches, each fifteen to twenty moves deep.

For a professional with a support team, this is routine work. For an amateur, it is an investment with no end date. And this is where the opening theory market operates.

I have spent many years watching how opening products are sold. The pattern is nearly fixed. Every product promises three things: few lines, easy memory, and a confused opponent. The difficulty lies in the word few. Few compared to what, and few down to what level, is never quantified.

In the material I am reading, there is not a single number. No win rate, no draw rate, no move-quality metric, no sample games cited. No author name, no title, no tournament record in the Mar del Plata. The product's entire credibility rests on one argument: this branch is harder to memorise, therefore it is better for you.

Based on my experience of following games, I have learned to distinguish two kinds of claim. The first is a technical claim, verifiable against a database. The second is a claim about experience, verifiable only by buying and playing. This product offers almost exclusively the second kind.

"COMPUTERS DON'T UNDERSTAND": A TRACE OF A PASSED ERA

One sentence in the promotional material made me pause longer than any other.

In substance: after 9...Nh5 the position opens up, the lines become forcing, and computer analysis becomes important again. After 9...a5, the game leads to sound positions with very few concrete lines, and computers often do not know how to handle such complex strategic positions.

That last sentence is a fossil.

I remember the period before 2026, when traditional chess engines still relied on search and material-based evaluation. They were extremely strong in tactical positions, where everything reduces to a forced sequence, but often clumsy in blocked positions, where the value of a move depends on a plan fifteen moves away.

The neural-network engine generation erased that gap. Modern engines evaluate closed King's Indian positions with the eye of a player who understands plans, not of a machine counting material. They still assess closed positions, still find the best move inside a locked structure, and sometimes produce moves no human would consider.

In other words, the argument that "computers don't understand these positions" is marketing language from the pre-AlphaZero era, pasted onto a product of the post-AlphaZero era. That does not make the product worthless. It only means the buyer should know what they are buying: an organised presentation, not a land no machine can reach.

This is also when I remember those pandemic evenings, when every pool was closed and I had to make a podcast to keep myself sane. The stands were empty, but the podcast taught me to listen to the game from inside. When the crowd is gone, you are forced to hear yourself. And when the computer is not the referee, you are forced to trust your own judgement -- even when that judgement is wrong.

Part of the appeal of a product like this lies exactly there: it gives the buyer the feeling that human judgement still has room. That feeling is not wrong emotionally. It is just packaged with a technical premise that has aged.

THE OPENING THEORY MARKET: A TRANSFER WINDOW WITH NO DEADLINE

In Vietnam, fans are used to two transfer windows a year in football. In chess, the transfer window runs all year, and the currency is not euros but moves.

The sellers are authors, publishers, online course platforms. The buyers are amateur players, young coaches, parents who want an edge for their children in junior tournaments. The merchandise is "antidotes" to popular lines.

A transfer is a symphony; the numbers are only notes. But in this symphony there is one instrument that is always forgotten: the free database. Every move in a DVD can be found there, alongside thousands of real games, played by real people, with real decisions.

So what makes a DVD sell?

Structure. A database answers the question "what move has been played". A curated product answers the question "what should I think about those moves". Between those two questions lies a gap large enough to sustain a small, durable and least glamorous industry in chess.

Inside that industry, every promise is sold with an asterisk. The promise of "very few concrete lines" does not mean there are no lines. It means the author chose not to list them. The promise of a "balanced position" is a positional judgement, not a theoretical discovery. And the promise that "if Black knows what he is doing, things quickly become dangerous for White" is marketing absolutism, not a conclusion drawn from data.

I say this not to belittle the product but to place it correctly. For a club-level player trying to escape memorisation addiction, it may be a useful tool. For a grandmaster, it is a chapter in a book they read long ago.

THE SAMARKAND TITLE AND THE INFORMATION TRAP

There is one detail I must mention, because it bears directly on how much you should trust this material.

The material I received carried a title about a team round in Samarkand, in which "all the top teams grabbed wins despite close calls". The body was entirely about a King's Indian opening DVD promoting the move 9...a5.

The two texts are unrelated. No team, no pairing, no result appears in the body. Conversely, no move appears in the title.

In my trade, this is one of the most serious warning signs. When a source does not match between its head and its body, everything else in that source must be placed in quotation marks until independently verified.

Samarkand is a genuinely important chess centre in Uzbekistan. That country has produced young players who made the whole world look again, and a team event held there is entirely plausible. But the plausibility of a title does not confirm the truth of a body.

What I take from this is not generic scepticism. It is a working principle: check the original catalogue, check the primary source, check whether the document you are reading is actually about what its title promises.

Because a product that teaches strategy while making a basic information-organisation error has at least given you one fact worth weighing before you pay.

HOW WHITE WILL COUNTER

Every opening theory is a temporary trench. That is the lesson I learned from standing at the edge of junior tournaments in central Vietnam, where coaches passed around photocopied sheets with a new move, and three months later those sheets were useless.

If 9...a5 is widely used, the White response will arrive in a fairly predictable sequence.

In the first phase, White will be surprised and will often handle it poorly. A move that looks harmless creates more errors than a move that looks violent, because it does not trigger defensive instincts. For one to three months after the branch spreads at amateur level, Black may harvest more points than the move is truly worth.

In the second phase, well-prepared players will re-examine the structure. Once Black trades on b4 and opens the a-file, that file becomes a two-edged asset. Black rooks can press on it, but so can White rooks. And in many closed positions, Black voluntarily opening a file creates an entry route for White that did not previously exist.

In the third phase, once the branch has been analysed to the bottom, its value returns to its true level: a good reserve option, not a decisive weapon. This is the common fate of every secondary branch in every opening. It is not defeated. It simply becomes normal.

The interesting thing is that the period of not-yet-normal is exactly what gets sold. The buyer is not paying for a move. The buyer is paying for a window in time.

AND HERE IS WHERE I DO NOT FULLY AGREE WITH HOW IT IS SOLD

I reread the product introduction several times, and three things made me uncomfortable.

The first is the way it is framed for a specific group of players: those who "like to think for themselves rather than memorise". This is an argument about identity, not about chess. It sells you an image of yourself -- the strategic player, the one who does not need to learn by rote -- and then sells you a product you still have to learn, just less of it. I understand the power of that marketing. I also understand that it has never made a young player genuinely stronger.

The second, and this is what truly concerns me: "few lines" is an unverifiable promise, and at a high level of chess it is rarely true in the sense buyers expect. The Mar del Plata is one of the sharpest systems in classical chess. Black's king sits on g8 behind a pushed pawn wall, and a single careless move in the centre can bring the whole house down. No move removes calculation from that position. A move can remove the need to memorise a long sequence. It cannot remove the need to count.

The third, and perhaps the most important for someone whose job is reading documents: the total absence of an author name. In chess, credibility is currency. A product on the Mar del Plata written by a player who has won many games in that branch is worth something very different from a product naming no one. The fact that the source does not tell me who the presenter is, what title they hold, how many games they have played in this branch and with what results means I cannot evaluate the most important part of the product: its selectivity.

There is a temptation I have seen in many sports writers, including myself in my twenties: turning empathy into sentimentality. When you side with the underdog, you easily write as if every small product is being treated unfairly. I have tried to avoid that here. This product is not bad. It is simply sold with arguments stronger than its actual merits, and that is a different, more specific and fixable problem.

WHO THE BUYER ACTUALLY IS

If I had to describe the customer for a product like this, I would describe three groups.

The first is club players whose rating hovers around the middle band, people who have played the King's Indian for years but never seriously analysed the Mar del Plata. For them, this product has real value. It provides a framework, an order of priorities for plans, and a sense of safety when entering a complex system.

The second is young coaches who need material to teach. For them, the value lies in the presentation structure, not the moves.

The third is the largest and least rewarded group: people who buy opening products as a way of postponing actually studying chess. I know this group well, because I once belonged to it. For years I collected opening material like a stamp collector. I had enough. I did not play much better for it.

In the silence of the stands, the future wears running shoes. Likewise, in the silence of an opening library, real progress happens somewhere else: in games with a person sitting opposite you, a clock running, and a mistake you have to own.

If this product helps someone sit down and analyse seriously for the first time, it has done its job. If it helps someone feel they have finished learning just because they finished watching, it has harmed them.

VIETNAMESE CHESS SEEN FROM THIS ANGLE

I live in Da Nang and report on chess for Vietnamese readers, so I cannot read a document like this without thinking about home.

Vietnamese chess over the past twenty years has moved from near-invisibility on the world map to having a permanent presence in the elite group. Le Quang Liem, Nguyen Ngoc Truong Son and the next generation, including names like Tran Tuan Minh, have proved one simple thing: Vietnamese players can compete at the highest level without a vast training system.

On the women's side, Pham Le Thao Nguyen and Nguyen Thi Mai Hung have helped keep Vietnamese women's chess present in regional arenas. And it is worth noting that in Vietnam, women's chess is treated somewhat better than in many places -- at least at amateur level, where women's events have a genuine place rather than being a line in a corporate social responsibility report.

That is a point I want to emphasise. On the international market, the commercialisation of women's events is often treated as an obligation, a line in an annual report rather than a genuine business opportunity. Women's tournaments are held for photographs, sponsored to tick a box, and promoted to say the industry has progressed. Much of that investment does not reach female players in any sustainable way.

The product I am analysing is not directly related to that story, but there is a common denominator. Both are systems built to look as if they serve the player, while actually serving the seller. And in both cases, the Vietnamese player -- especially young players in the provinces, where study material is scarce and tuition fees are a real consideration -- bears the highest cost for an unverified promise.

A NOTE ON DATA

I want to say something rarely said about the heat maps and analysis charts flooding every sports feed today.

They are becoming a new form of fortune-telling. When you colour squares on a board according to how many times a piece passed through them, you create the impression that you understand that piece's role in the tactical system. You do not. You only know where it was.

I have seen young coaches in Da Nang print charts like these and hand them to students. Those charts are not wrong. They simply answer the wrong question. A rook that has stood still in a corner for twenty moves can be the most important piece on the board, and a heat map will paint it blank white.

In the material about this DVD, no heat map is offered, and that is actually a kindness. But no other number is offered either, and that is the difficulty. A product teaching strategy without a single quantitative datum forces the reader to trust the author's voice. In this case, the reader does not even know whose voice it is.

I TRIED IT ON THE BOARD

I did not want to write about a move without touching it myself.

The next evening I opened a board on my machine and played ten blitz games against myself, one side playing the Bayonet, one side playing a5. I deliberately did not check a database first, so that part of my mind had to struggle the way the fourteen-year-old in the coffee shop had.

The result is not scientific, and I do not present it as evidence. Ten games is far too few to conclude anything about the theoretical value of an opening branch. Blitz is also not the place to evaluate a position that requires patience.

But I learned something about feel. When I held Black and played a5, I found myself thinking more slowly. I was no longer waiting for my opponent to follow the book so I could continue. I had to see the board as a surface, not a pipeline.

That is exactly what any good opening product should do. It does not make you stronger by giving you more moves. It makes you stronger by changing how you look. The only problem is that you can achieve that for free, by sitting with a position for thirty minutes and asking yourself the right questions.

WHAT WOULD CHANGE MY ASSESSMENT

I always want to leave a list of things that could refute my conclusion. If you held me here and asked what would make me say otherwise, I would answer with four signals.

One is the appearance of 9...a5 in a classical game at the highest level, with a long time control, between two leading players. Such a game would not prove the move stronger. It would prove the move serious enough for people to dare use it when everything matters.

Two is the frequency of the Bayonet. If over the next few years 9.b4 remains a popular choice, the product's time window stays open. If young players shift to other approaches against the Mar del Plata, the product becomes obsolete at the same moment as its own subject.

Three is locating the original document. If the Samarkand title and the DVD body are two texts spliced together by mistake, that confusion says nothing about the DVD's technical quality. It says something only about the quality of the distribution chain. But if either part was deliberately distorted, the story changes entirely.

Four is the author's name. A name with a real record in the Mar del Plata would turn an advertisement into an assessable document. In chess, that matters more than any promise about the number of lines.

We will keep tracking these signals. When they appear, you will read about them here.

TAKEAWAY

The boy in the coffee shop on Nguyen Chi Thanh Street that evening did not know where he stood in the history of chess theory, and that did not matter. What mattered was that he pushed the pawn to b4 without hesitation, simply because he was curious to see what would happen.

An a5 in a DVD sold in Europe, a Samarkand title from a team round, a heat map printed in a classroom in central Vietnam -- all of these are just different ways people try to understand a game that never stands still.

From the long-jump runway to the virtual arena, the homeland of sport has no borders. And on the chessboard as on the running track, the one thing money cannot buy is the ability to sit still and think for yourself.

If there is one move worth learning right now, it is the move no product can sell you: the one you find when nobody is standing beside the board.