Chess players memorise openings because the pieces start in fixed positions and the same structures appear again and again. Gomoku is different. The board starts empty, and after a handful of moves most games are already unique. Memorising long sequences is far less useful than understanding a few principles that tell you what a good early move looks like.
This article gives seven principles for the first ten or so moves. They apply to freestyle gomoku and to Vietnamese caro with the blocked-ends rule, and they work whether you are X or O.
1. Start near the centre
The first move almost always goes on or near h8, the centre of the 15×15 board. A central mark belongs to far more potential fives than a mark near the edge — twenty for the exact centre, compared with three for a corner. More potential fives means more ways to build threats later.
The second player should also stay near the centre, close to X's first mark. Playing far away gives X free development.
2. Keep your marks close together
In gomoku, marks work together only when they are near each other. Two marks five points apart on the same row are not really a line; two marks side by side are the start of one. Early in the game, place new marks within one or two points of your existing ones.
This is sometimes called playing compact or connected shape. Compact shapes produce threats in several directions at once, which is exactly what you want when the fighting starts.
3. Build on crossing lines
Every point sits on four lines. The best early moves are those that add to two or more of your potential lines at once. If your two marks are on h8 and g8, then g9 builds a column with g8 and a diagonal with h8, while h9 builds a column with h8 and a diagonal with g8.
Crossing moves are the raw material of later double threats. A player who habitually builds on crossings finds four-threes and double threes much more often.
4. Grow toward open space
Before extending a line, look at how much room it has. A line pointing toward the opponent's marks or the edge has fewer ways to become five — and under the blocked-ends rule, a line that already touches an enemy mark is half dead. Prefer to extend toward empty space.
This principle matters more as the game fills up. In the first two or three moves nearly everything is open; by move ten, the direction of each line matters a lot.
5. Stay close to the opponent's marks
This sounds like it contradicts principle 4, but it does not. Your marks should be near your own and also near the opponent's. A mark placed next to an opponent's two limits their growth in that direction while building your own shape. Marks placed far away from the action do nothing for either purpose.
For O in particular, staying close is essential. X moves first and builds faster; O's early marks must interfere with X's shape, not start a separate game elsewhere.
6. Do not force too early
It is tempting to make a four as soon as you can, because it forces the opponent to answer. But a four spends one of your lines: once the opponent blocks it, that line is usually finished, and under blocked ends it may be dead forever. Early fours rarely gain anything.
In the opening, prefer building twos and open threes in several directions. Save your forcing moves for the moment they set up a combination. The same goes for open threes: an early open three is fine, but only if the opponent's forced block does not help them.
7. Count tempo
At every moment one player is making threats and the other is answering. The player making threats has the initiative. In the opening, X naturally has it; O's job is to take it away.
A quick way to track tempo: after each move, ask does the other player have to answer this? If yes, the mover gained a tempo. If no, the opponent is free to build. Good opening play is largely about not giving away free tempi — see keeping the initiative.
Putting the principles together
Here is how the principles look in a typical short opening, described in words.
X starts at h8. O answers at i9, diagonally adjacent — close to X (principle 5) and central (principle 1). X plays g8, making a two on row 8 with room on both sides (principles 2 and 4). O plays h9, next to both its own i9 and X's h8, building its own row-9 two while limiting X upward. X could play g9, building column g — but that mark would sit right beside O's h9 and run into O's shape. A cleaner choice is h7, building a column two with h8 below the O marks and an anti-diagonal with g8, heading toward open space.
No single move here is "the book move". What makes them good is that each one follows several principles at once.
Principles under blocked ends
All seven principles apply to Vietnamese caro, with two adjustments:
- Principle 4 becomes stronger. Because a line blocked at both ends is dead, growing toward space is even more important.
- Principle 6 becomes stronger. Early fours under blocked ends are particularly wasteful, because the forced block often kills the line permanently.
How to practise
Play a few games against the computer on the home board with one opening principle as your focus. For example: "In this game, every one of my first eight moves must add to two lines." Afterwards, replay the opening from your account and check whether you kept to it.
When you are comfortable, try the same exercise as O. You will find principle 5 — staying close — becomes the most important.
Frequently asked questions
Do I need to memorise gomoku openings?
Not for casual or intermediate play. Principles matter much more. Serious renju players study named openings, but that is a specialist area.
Where should the first move go?
On the centre point, h8, or very close to it.
Should O play adjacent to X's first move?
Usually yes — directly or diagonally adjacent. Playing far away gives X free development.
Is it good to make an open three early?
It can be, if the opponent's forced block does not help them. Do not make threats just because you can.
Do the principles change under blocked ends?
They stay the same, but growing toward open space and avoiding early fours become even more important.
