INCHWORM

Copyright (c) 2000 Clark D Rodeffer

This game is played on an 8x8 empty square board.

Each player starts with 25 stones off board (in the diagrams, a dot represents 5 stones).

STACK - One or more stones of the same color stacked on the same cell. A stack is free if it is (orthogonally) adjacent to an empty cell. TURN - On each turn, each player must do one of following things: He may drop exactly one of his stones onto any empty cell. He may drop exactly one of his pieces on top of one of his stacks, thus increasing its size. Collect a connected group of his stacks into a single combined stack. Stacks so collected may lie along any straight line or diagonal. Distribute one of his stacks into a winding group of individual pieces beginning with the cell where the stack started. In distributing stones, any path may be taken, including straight lines and diagonals, but the entire stack must be distributed into individual stones. Capture - By doing this, those enemy stacks with no liberty (i.e., a group of orthogonally connected enemy stacks with no orthogonal adjacent empty cells) are captured. The player gets one point for each stone in those stacks. However the stacks are not removed by this move (check next option). Rescue all prisoners held by his opponent and returning them to his stock. Points are not lost when stacks are rescued; they only return to their original owner's stock. GOAL - The first player to score at least 60 points wins.

Notes on captures (from the author):  Any individual pieces and/or stacks of pieces that are orthogonally surrounded, including those trapped against one or more edges of the board, by opposing pieces or stacks of pieces may be taken as prisoners and scored, no matter how those pieces came to be surrounded. Playing so that your own pieces are captured is perfectly fine, and may even be a useful tactic if your stock is empty or nearly so, or if opposing pieces are simultaneously captured by such a move.

An example The Black stack at a8 and the group of two Black stacks at a3-a4 may be captured by White. If Black were to play at h1, only the played stack would be captured by White; however, if Black were to play at h8, the played stack would still be captured by White, but Black would also capture the group of three White stacks at g7-g8-h7.

Some more notes from the author:

Variations - A variation that makes capturing more difficult (and hence lengthens the game) is to eliminate the side and/or baseline board edges, wrapping them around like a cylinder or sphere, respectively. Capturing on a cylindrical board is more difficult than on one with edges to the side, and capturing on a spherical board is even more difficult. Another variation that increases offensive potential is to allow placement of captured opposing pieces. Their usefulness in filling eyes in your opponent's formations can increase game tension and result in faster scoring. However, this can lead to a trivial situation where opposing pieces are repeatedly played into the eyes of your own formations and recaptured and scored over and over again, reducing the game to a race. Handicaps - If one player is noticably stronger than the other, a fair handicap system is for the stronger player to use fewer pieces. As the stock empties, the stronger player will need to spend more turns rescuing his prisoners, thereby giving the weaker player a few extra turns to gain positional advantages. One or two pieces constitute a relatively minor handicap, but five pieces is significant. Strategy Making eyes (unfilled areas surrounded by your own pieces) as in Go is a useful strategy for preventing your opponent from scoring points. However, as in Go beware piece formations with only one eye, as these may allow your opponent to capture entire groups at once. On the other hand, formations with two eyes take many pieces, and if there are no stock pieces, a player may be forced to break up a stable formation to form or distribute a stack.  Don't become too attached to your pieces. Both players will capture many opposing pieces, and in fact, that's the idea of the game. But captured pieces can be rescued and dropped inside vulnerable formations controlled by your opponent. A small sacrifice can be worth several points.  If your opponent has a stable formation with two or more eyes, try to immobilize your opponent's other formations by crowding them together and/or against an edge or corner of the board. Eventually, your opponent's stock will run out, and he will be forced to distribute or (more likely) form a stack. Often these new stacks are easy to capture. Try to keep at least a few pieces in your stock. Since they can be dropped on any empty board space or on top of any of your own stacks, stock pieces are the key to tactical flexibility.  Know how many pieces are required to surround and capture any formation, both your own and those of your opponent. Defense in the center is easier than near the edges, but easy attacks near the edges can leave many vulnerable pieces for your opponent to capture. One piece in the open requires at least four pieces to capture it, and lengthening a group in the open by one requires two more pieces -- an advantage to the defense. But space on an 8x8 board is at a premium, and once pieces get more crowded, defense becomes more difficult. Wait either until you have only two or three stock pieces left or until your opponent has just made a big capture before rescuing prisoners. This minimizes the number of turns wasted rescuing prisoners. Of course, if there are no attractive moves available, and since passing is not allowed, rescuing prisoners at other times may be a good tactic.