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Ketchup Strategy Basics, Plus an Example Game

October 27, 2011

Another post about my game Ketchup. I’ll wait here while my game-designer friends who endure my frequent discussions of this game go and retch in a corner. Done? Ok here goes.

This time I’m indulging my enthusiasm with strategy notes. If you don’t know the rules, read this first.

There’s still much I don’t understand, so while these notes help you against players who have what now passes for experience, and to trounce noobs, they won’t make you an expert so much as slightly prevent idiocy.

Key Strategy Concepts

First is the central rule of thumb: if you take the lead, you’ll be giving an extra stone to your opponent. Therefore don’t take the lead unless, by doing so, you ensure that at least one of your opponents’ stones on board will be separated from his largest group. i.e. don’t give away a stone without taking at least one (and preferably more) back at the same time.

The winning player’s stones usually end up in one of 4 possible kinds of patterns, or as a hybrid of 2 of them. Being aware of the 4 patterns makes you instantly better. On every turn, try to see which of the patterns are most achievable for you, and which are most achievable for your opponent. This will guide both your offensive and defensive choices. Here are the 4 patterns:

The Fork:

Fork

This pattern is one of the most common in hex-board connection games: a chain of stones dividing the board into three segments, profoundly limiting your opponent’s ability to create a large group.This is how experienced players shellack newbies. It only happens when the losing player is terrible or makes a dumb mistake, as it’s easy to prevent.

The Knife:

Knife

This is the Fork’s more achievable but less-powerful sister. It’s a chain of stones dividing the board approximately in half. As with the Fork, it limits your opponent’s ability to build a big group, but not as much, and as with the Fork, you usually have to give up bonus stones to your opponent in the attempt. This creates two problems:

  1. If you fail to get all the way across, you can end up losing to a Wrap pattern (see below)
  2. Even if you get all the way across, you can end up losing to the Sandwich pattern (see below)

The Wrap:

Wrap

This pattern often comes into play when one player tries too hard to secure the center of the board (as connection-game players often do, because the center of the board is more important in most connection games than it is in Ketchup). The idea is to let your opponent dominate the center, but as she does, you create a containment perimeter around it, the ends of which are anchored to the edges such that her center clump is cut off from much of the board. To pull this one off, you have to force your opponent to take the lead to secure the center, which gives you bonus stones with which to build your perimeter. The difficulty with this one is that it takes a lot of stones.

The Sandwich:

Sandwich

If you see that your opponent is trying for a Knife, you can try to build this to neutralize it. The idea is to build parallel flanking walls to your opponent’s knife. It usually works best when you subtly push your opponent into making a knife which doesn’t run directly across the middle, but rather is shifted or bent so that the board isn’t evenly divided. Your opponent will usually be forced to take the lead to create a Knife, which will give you extra stones with which to make a Sandwich. As with the Wrap, the Sandwich takes a lot of stones to make.

As I’ve mentioned, the winning pattern often ends up being a combination of 2 of the above patterns. Example: sometimes you may be going for a Knife, and thanks to an oversight of your opponent, you may be gifted a sudden opportunity for a Wrap, so you bend the ends of your Knife toward one side of the board and wrap around your opponent’s largest group there.

A caveat: it’s hard to plan any of these patterns from the beginning if you’re opponent is aware of them. Instead, the best I have been able to do is create an opening that keeps me open to at least two of these patterns and then make a run for one of them when I get an opportunity. I’m beginning to develop opening concepts however, so I may have more advice to offer on this point soon.

Key Tactical Concepts

A key goal is to avoid giving extra stones to your opponent. The only way to do so is to keep your groups small. But then the only way you can win is by retaining the capacity to connect your small groups into an unbeatable big group later. How to do that? Answer: by creating strong virtual connections. This is a more subtle task than in normal connection games and is one of the main reasons I love this game. Here are two important virtual connections:

The Conditional Stretch:

Cstretch

The picture above shows a conditional stretch between White groups. Consider what would happen if Black tried to prevent White from connecting his 2 groups together: if Black placed 2 stones in the gap between White’s groups, White could then place three stones around the end and connect his groups anyway. Note that the conditional stretch is breakable if your opponent can place 2 stones in the gap without giving you a bonus stone (which Black can’t do in the picture). This means you can only establish a conditional stretch in certain places in on the board, relative to your opponent’s stones. An important part of the game is to manipulate your opponent’s placements so that you can secure conditional stretches in key spots.

The 3-way Stretch:

3stretch

The picture above shows a 3-way stretch between White groups. This is like a conditional stretch except it takes 3 stones to fill the gap instead of two, which makes it much harder to break. On the other hand, it’s expensive to create this connection since it requires 4 stones minimum. Sometimes your opponent will forget to keep an eye out for it, because it’s not something that comes up all the time, and if she fails to defend against it, it can give you a powerful edge.

When the Two Largest Groups End Up Being The Same Size

This happens often (~10-30% of my games with similarly-skilled players), and I believe that as players improve it will happen even more often. If you want to be good, you have to learn to make sure your second-largest group is bigger than your opponent’s second largest group. This opens a realm of strategy/tactics of which new players aren’t aware. It’s a realm that I’m only now exploring, so my ideas about it are tentative. In fact the only thing I can say confidently is that it increases the value of the sandwich, because the sandwich is the best choice for creating a large second group. Now, most of the time I only end up creating a sandwich in response to something my opponent does. I have yet to try planning a sandwich from the outset. If it’s possible to do so with any success, the sandwich may be powerful.  Flip through the following pictures to see an example game in which both players end up trying to Sandwich each other at the same time. Both players succeed to about an equal degree, the two largest groups end up being the same size as a result, and white ends up winning because he made smarter (and earlier) efforts at building his second-largest group (see turns 14 through 19 for his key moves in this regard).

Ex1
Ex2
Ex3
Ex4
Ex5
Ex6
Ex7
Ex8
Ex9
Ex10
Ex11
Ex12
Ex13
Ex14
Ex15
Ex16
Ex17
Ex18
Ex19
Ex20
Ex21
Ex22
Ex23
Ex24

(This game was a test game played without a scoring track, which makes it harder to follow. Apologies for that.)

I’m convinced that high level play will almost always require players to attend to their second-largest groups, and maybe even their third-largest. It may be a good idea to track your two or three largest groups by using multiple stones on the scoring track. Good players will probably graduate to larger boards, and that will only strengthen the need to strategize around multiple groups. I’m excited for this to happen because I think the game will flourish under those conditions.

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From → Essays

2 Comments
  1. Tensesquirrel01 permalink

    interesting game

  2. Nick Bentley permalink

    thank you kindly

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