Today I’d like to talk about induction. It’s a concept that I frequently find myself explaining when reviewing teaching games, so I’d like to have a page about it to refer people to. It’s also a very interesting and effective way of thinking about the game of Go, especially in fighting positions.
Induction in the game of Go
Induction is a broad concept that can be applied to many different situations. At its most basic, induction refers to playing a move that forces the opponent to respond in a predictable manner, so that you will then be compelled to play a move that you wanted to play anyway. That’s all a bit wordy, the diagram on the right probably explains it better. In this contact fight, black wants to defend at 3, but he exchanges 1 for 2 first. This means black gets an extra move in at 1, it also makes better shape for black and makes white slightly heavier. Black 1 is a basic tesuji.
In larger scale fighting positions, induction is also an important concept for making your stones work together more efficiently. Sometimes you hear players talk about the ‘natural flow‘ in fighting situations and this is very much a related concept; one move induces the next in a kind of chain reaction. The game I’m going to show here is one I studied a few years ago, where I first began to really understand how to use induction in the middle game.
This is an old game, but it still has lessons for us today. The game is from early in Shusaku’s career and is not quite as polished as some of his later games. The moves up to 27 bring us to the position of interest. The negotiations at the top have come to a standstill and now white wants to help his floating group in the centre. It’s worth stopping to think about how you would play as white here.
How would you help the floating white group?
In the game white played 1. This made black come out at 2 and induced white to develop the centre group with 3, as he wanted to anyway. White 1 exemplifies the proverb “If you have to run, then bring a friend.” White thinks, I have a weak group, I can’t make a base, so I’ll take away black’s base instead. That way both players will have weak groups to worry about, and neither can attack the other too aggressively. In other words, white 1 leads to a fair fight. This is a key idea in using induction.
Instead of 1, if white trades ‘a’ for ‘b’ (on the left) then black’s group will be almost settled and white will still be floating. Also, instead of 1 if white tries ‘c’ then black ‘d’ and white’s shape is too thin to continue applying much pressure. Both white ‘a’ and ‘c’ just help black to settle quickly.
Black 4 might look a bit insipid, but I think it’s the best move. The reason…
Giving white control
…If black plays elsewhere (let’s consider 1 and 3 for example), white plays 4 and takes complete control of the flow of the game (see right). Black has to “push the cart from behind,” with 5 and 7 while white happily takes profit with 6 and 8. And black isn’t out of the woods yet.
White 4 is a very satisfying move to play. One of my friends, who taught me a lot, often says “Why make territory by yourself? It’s much more fun to force the opponent to help you make territory.” This diagram is a good example of that idea.
Notice how white 4 ends up on black’s key point “at the centre point of three stones,” depriving black of eyeshape. Note also that if white doesn’t exchange 2 for 3 before playing 4, black might decide to play for a trade with ‘a, b, c’. After ‘c’ white can’t stop black from capturing some cutting stones.
Let’s step to the left…
Since black 1 (above) defends against white ‘a’, white switches to 2 (which was white’s miai). Now if black turns to attack white’s lone stone on the right, white will ignore it and pincer at ‘b’ (or ‘c’). This would be quite severe so black defends with 3. If you stop to think about it, all the moves from white’s one space pincer (marked) up to 3 in this diagram are, in a sense, the natural continuation of that pincer.
If you don’t already understand this concept well, you should try to grasp the feeling of how all the groups develop towards the left of the board after the marked stone is played. In Go, there are often times where a sequence of moves is practically forced. There are also frequently times where you reach a crossroads, and the direction you choose will dictate the development of the game.
White decides to take a big point with 4 and get ready for the next round of fighting. It’s worth noting that if black already had a stone at 4, he might have played 1 at ‘d’ (inducing black 1). If this was the case, I would think the triangled stone was an overplay. Obviously that’s not the case in this game though. Where should black play next? A move at ‘e’ seems to be the pivot point for both groups, but should black play there directly or try something else?
Both players follow the rhythm
In the game black chose 1, an inducing move that provokes 2 and 3. If black played 1 at 3 directly, white might just finish his territory in the lower right by playing ‘a’. After that black would have little to look forward to in this area. White could play this way because after 3 black still can’t surround white’s centre group with a single move.
Another sequence worth considering is: black ‘e’, white 3, black ‘b’ white ‘a’. Presumably black rejected this line because he didn’t want white to play ‘a’ and he didn’t want white’s group to get shape with 3. If you look at that sequence objectively, black seems to be attacking at ‘e’, but he lets white take the key point at 3 as well as territory at ‘a’. (In this sequence, a white knight’s move at the point between 1 and 2 might be more effective for attacking than white ‘a’. It’s difficult for me to choose in this situation.)
Some readers might feel that after white 4, black’s move at 1 seems to be an overplay. All I can say about that is black 1 is definitely a fighting move and the line between a strong move and an overplay is often very fine. However, if white jumped again with 6 at ‘c’ then black would simply play ‘d’. After that white wouldn’t have time to defend against both ‘e’ and ‘f’. White’s top centre group is heavy whereas black’s lower right stones are light and flexible. White can’t really expect to trade groups without taking a loss, which is why black can play the way he does in the game. Next move anyone?
The capping move, induction again
Yet another inducing sequence. The capping play (black 1 above) is often a key point for attacking and slowing your opponent’s development. In this game it also sets the sequence to 3 in motion and builds a framework in the top left. There’s a greedy little Go player in my head who tells me to play ‘a’ as soon as I see this shape, but first let’s read a bit and see if white ‘a’ is actually any good.
After white cuts with 1 and 3 (on the right), the fighting would probably continue like this and white appears to be dead… It’s important that black doesn’t play 4 at 5 or white will cut at 4. White 7 is a common shape move which is often useful for escaping, but it fails here.
This sequence illustrates the importance of reading. Another advantage of reading is that it gives you hints to help you find moves that threaten your opponent indirectly.
For example, how would you play instead of 1 in the diagram?
Thus, in the game white makes shape with 44 (above). If black responds at ‘a’ or ‘b’ then the sequence I gave above is broken and white may successfully cut starting with c. For that reason black cleans up the aji with 45 and now the sequence of white ‘c’ through to black ‘h’ just leaves white with a dumpling while black remains connected. We’ll stop following the game here, but for those who are curious, white won by 1 point.
When you first start trying to use these ideas in your own games it can be hard. I remember I made many mistakes and many overplays (and still do in fact) trying to apply this concept. As you practise more though, moves like this begin to seem very natural, almost like second nature.
Well, that’s the end of this post. I hope you learned something. I plan to follow this up later with a post on how and when to resist your opponent’s plan and play ‘unnatural’ moves. Here’s the game record for anyone who wants to play through it.
Game record: Honinbo Shusaku vs Kishimoto Saichiro – 1843