A board game, named for the unusual form of the board.

As with games like Othello and Abalone, the rules of play are
few and simple, but form a complex game. Unlike most games (and
offhand I can't think of another one), there are two distinctly
different ways to win, which could be thought of as being
offensive and defensive.

This is my second favorite board game, after chess. I highly recommend it!

**Note: This writeup was originally done using HTML tables with colored cells, which
made it much easier to visualize the three-dimensionalness of the board,
which is an integral part of the game, before I knew that that wasn't
allowed in E2. You can find that version of this writeup at
http://www.silcom.com/~clarence/terrace.html**

# The Board and Pieces

The board is an 8x8 grid, like a chess board, except that the
four quadrants are terraced. Letting **8**
be the level of the highest square and **1** the lowest, the
board is built like this:

1 2 3 4 5 6 7 8
2 2 3 4 5 6 7 7
3 3 3 4 5 6 6 6
4 4 4 4 5 5 5 5
5 5 5 5 4 4 4 4
6 6 6 5 4 3 3 3
7 7 6 5 4 3 2 2
8 7 6 5 4 3 2 1

To help you visualize it, note the *L*-shapes formed by
neighboring squares with the same number, for example the 3s.
That *L* consists of five squares all at the same level, with
three squares "inside" the *L* at a lower level, and seven
squares "outside" the *L* at a higher level.

There are four kinds of pieces, which are hemispheres of differing sizes.
In the normal two-player game, each side starts off with four of each size.
Letting **A**, **B**, **C**, and **D** denote the largest
through the smallest pieces respectively, the pieces are originally arranged
as follows.

T D C C B B A A
A A B B C C D D
D D C C B B A A
A A B B C C D T

Again, to help you visualize, remember the steppes on the board, and see
that each player has the row closest to him filled with large pieces at
his left, shrinking as you proceed to the right side of the board while
the levels also become lower. In a symmetric fashion, the second row from
each player starts with a small piece at the left, growing to the largest
size at the right.

You'll notice that one of the **D**s for each side (the one on the
lowest square) has been replaced by a **T**. The **T** is the
same size as a **D**, but is special because it is involved in
winning or losing the game.

# How Pieces Move

| A B C D E F G H
-+-----------------------
1| l A
2| l B u
3| l B l l u
4| u u u l C **C**
5| x
6| **B** d
7| D
8|

Here, the uppercase letters represent pieces, the lowercase letters are
used only to identify vacant squares.

On each turn, a player can move one piece. The possible kinds of moves
are:

- Level: You may move a piece along the level it is on, as many spaces
as you like, except that it cannot move past an opponent's piece, or
one of your own larger than the piece being moved. For example, the
**B** on B3 has four possible level moves (marked with a *l*).
However, the **C** on 4F has only two level moves available to it, because
it can pass neither its own **B** (it's bigger) nor the opponent's
**C**.
- Up: You may move a piece to the next higher level, either straight up
or diagonally, to an empty square . The
**B** on B3 has 3 available
*up* moves, marked with a *u*. The **B** on E2 has
only two *up* moves, because one of its *up* neighbors (F1)
is occupied.
- Down: You may move a piece straight down to the next lower level to an
empty square. You may also move a piece down diagonally, but only
onto a square
**occupied** by a piece the same size or
smaller. This is the capturing move in Terrace. The **B** on 6D
can move straight down to 6E, or can capture the **D** on 7E because
it is down and diagonal, and not larger; however, it
cannot move to
5E (marked with an *x*) because a down diagonal move
**must** capture a piece.

Note that you can equally well capture a piece of your own as one of your
opponent's! Thus, the

**A** on F1 can move to E2, capturing its own

**B**.

Also, a piece cannot move from 4D to 5E (or vice-versa) (even though they're
at the same level).

# Winning the Game

As mentioned at the beginning, there are two ways to win the game.
Offensively, you win if you capture the opponent's **T**; defensively,
you win if you move your **T** to the opposite corner of the board
from where it started (i.e., to where your opponent's **T** started).