## Help For Tanbo

### Introduction

Welcome to the network Tanbo server. The rules of Tanbo are below. The Tanbo "challenge" command is described here. Other commands are the same for all pbmserv games.

Current games can be viewed here.

tanbo challenge [ -small | -beginner ] userid1 userid2 [ userid3 userid4 ]
Start a new game between userid1 and userid2
-small|-beginner allows player to play the smaller 9x9 board.

Tanbo support games with two or four players. Three cannot play because there is no fair and symmetrical starting position.

### Tanbo Rules (Copyright (c) 1995 Mark Steere <mark@tanbo.com>)

AUTHOR'S NOTE: Feel free to distribute this document.

```I   INTRODUCTION
II  RULES AND OBJECT
III THREE DIMENSIONAL TANBO
IV  OTHER DIMENSIONS
V   ORIGINS

I  INTRODUCTION
===============

TANBO IS LIKE GO
----------------
Tanbo requires a Go board and Go stones.  As in Go, players take turns
adding their stones to the board, and occasionally a group of stones
is removed.

TANBO IS NOT LIKE GO
--------------------
In spite of its similarity to Go, Tanbo is basically a different
game.  For example, there is no score in Tanbo.  The object is to

TANBO IS A GAME OF ROOTS
------------------------
Tanbo crudely models a system of plant roots.  Roots which are
growing, competing for space, and dying.  In beginner play, the roots
grow much as the roots in a garden. Over time, the roots become shrewd
and calculating.

FIGURES A - D are excerpts from a novice game.  FIGURE A is the
initial configuration.  FIGURES B AND C show roots growing and
competing for space.  In FIGURE D, white has won by eliminating the
eight black roots.

FIGURE A: INITIAL SETUP - 16 SEEDS
#=BLACK, O=WHITE
A B C D E F G H J K L M N O P Q R S T
19   # . . . . . O . . . . . # . . . . . O   19
18   . . . . . . . . . . . . . . . . . . .   18
17   . . . . . . . . . . . . . . . . . . .   17
16   . . . , . . . . . , . . . . . , . . .   16
15   . . . . . . . . . . . . . . . . . . .   15
14   . . . . . . . . . . . . . . . . . . .   14
13   O . . . . . # . . . . . O . . . . . #   13
12   . . . . . . . . . . . . . . . . . . .   12
11   . . . . . . . . . . . . . . . . . . .   11
10   . . . , . . . . . , . . . . . , . . .   10
9   . . . . . . . . . . . . . . . . . . .    9
8   . . . . . . . . . . . . . . . . . . .    8
7   # . . . . . O . . . . . # . . . . . O    7
6   . . . . . . . . . . . . . . . . . . .    6
5   . . . . . . . . . . . . . . . . . . .    5
4   . . . , . . . . . , . . . . . , . . .    4
3   . . . . . . . . . . . . . . . . . . .    3
2   . . . . . . . . . . . . . . . . . . .    2
1   O . . . . . # . . . . . O . . . . . #    1
A B C D E F G H J K L M N O P Q R S T

FIGURE B: ROOTS SPREAD VIA HORIZONTAL AND VERTICAL
ADJACENCIES.  CLUMPS AND CLOSED LOOPS ARE
NOT PERMITTED.
A B C D E F G H J K L M N O P Q R S T
19   # . . . . . O . . . . . # . . . O O O   19
18   . . . . . . . . . . . . # # O . O . .   18
17   . . . . . . . . . . . . # . O . O O .   17
16   . . . , . . . . . , . . # # O O O # .   16
15   . . . . . . . . . . . . . . # # # # .   15
14   . . . . . . . . . . . . . . . . . # #   14
13   O . . . . . # # # O . O O O . . . . #   13
12   . . . . . . # . . O . . O . . . . . .   12
11   . . . . . . # . O O O O O O . . . . .   11
10   . . . , . . . . O , . . . . . , . . .   10
9   . . . . . . . . . . . . # . . . . . .    9
8   . . . . . . O . . . . . # . . . . . .    8
7   # # # . . O O # # # # # # # # . . O O    7
6   . . # . . O . . . . . . . . # O . . .    6
5   . . . . . . . . . . . . . O O O # . .    5
4   . . . , . . . . . , . . . O . , # . .    4
3   . . . . . . . . . . . . O O . . # . .    3
2   . . . . . . . . . . . . . O . . # . .    2
1   O O . . . . # # . . . . O O . . # # #    1
A B C D E F G H J K L M N O P Q R S T

FIGURE C: 16 ROOTS COMPETE FOR SPACE.  SEPARATE,
LIKE-COLORED ROOTS MUST NOT BE JOINED.
A B C D E F G H J K L M N O P Q R S T
19   # . . # . . O . . . . . # . . . O O O   19
18   . . O # O O O O O O . . # # O . O . .   18
17   . O O # # . . . . O . . # . O . O O .   17
16   . . O # . . . . # , # # # # O O O # .   16
15   . . O # . . . . # # . . . . # # # # .   15
14   . . O # . . . . # . . . . O . . . # #   14
13   O O O # # # # # # O . O O O . . . . #   13
12   . . . . . . # . . O . . O . . . . . .   12
11   . . . . . # # . O O O O O O O O . . .   11
10   . . . , . . . # O , . . . . # # # # #   10
9   . . . O O O O # O . . . # # # O . . O    9
8   . . # . . . O # . . . . # . . O O . O    8
7   # # # . . O O # # # # # # # # O . O O    7
6   # . # . . O . . # . # . # . # O . O .    6
5   O # # . . . . # # # O . O O O O # O .    5
4   O . # # # # # O . , O O . O . , # O .    4
3   O . # . # . O O O O O # O O . . # O O    3
2   O . # . O O O # # # # # . O . . # . #    2
1   O O O O O # # # . . # O O O O # # # #    1
A B C D E F G H J K L M N O P Q R S T

FIGURE D: WHITE WINS BY ELIMINATING THE 8 BLACK ROOTS.
A B C D E F G H J K L M N O P Q R S T
19   O . O . O . O . O . O . . O O . O O O   19
18   O . O . O O O O O O O . . . O . O . .   18
17   O O O O . O . O . O . . . O O . O O O   17
16   O . O , O O O . O O . . . . O O O . O   16
15   . O O O . . O . O . O O . . . . . . .   15
14   O . O . . . . O . O . O . O O O O O O   14
13   O O O O . . O O . O . O O O . O . O .   13
12   O . . O O O . O . O . . O . O . . . .   12
11   O O O . . . . O O O O O O O O O . . .   11
10   O . O O . . . . O , . O . . . , . . .   10
9   O . . . . . . . O O O . . . . O . . O    9
8   O . . . . . . . O . . . . . O O O . O    8
7   . . . . . . . . . . . . . . . O . O O    7
6   . O . . . . . . . . . O O . . O . O .    6
5   O O O O O O . . . . O . O O O O . O .    5
4   O . . O . O . O . , O O . O . , . O .    4
3   O O . . O . O O O O O . O O O O . O O    3
2   O . . . O O O . . . . . . O . O . O .    2
1   O O O O O . . . . . . O O O O . . . .    1
A B C D E F G H J K L M N O P Q R S T

II  RULES AND OBJECT
====================

EQUIPMENT
---------
Tanbo requires a 19 by 19 Go board, 180 white Go stones, and 181 black
Go stones.  One player takes ownership of the white stones and becomes
"white".  The other player is "black".  In the diagrams, white is "O"
and black is "#".

INITIAL SETUP
-------------
Initially, each player has 8 stones on the board as shown in Figure A.
The stones are interspersed and evenly spaced over the entire board.

BASIC MOVES
-----------
After setting up this initial configuration, black makes the first
move.  (A "move" will always mean adding exactly one stone to the
board.  Stones are never actually moved from one point to another on
the board.)  Next white makes a move, and the players continue to take
turns adding their stones to the board until one player wins.

A newly added stone must "connect" to exactly one stone of the same
color, which is already on the board.  Two points "connect" if they
do not connect.  Several examples of legal and illegal moves appear
in the following sections.

Players are not allowed to pass.  You must add exactly one stone to

FIGURE E: EXAMPLES OF LEGAL AND ILLEGAL MOVES FOR WHITE.
LEGAL WHITE MOVES: T18, P19, R9, M12
ILLEGAL WHITE MOVES (NO CONNECTION): N4, J12, K8, K2
ILLEGAL WHITE MOVES (2+ CONNECTIONS): F15, G5, B14, B12
A B C D E F G H J K L M N O P Q R S T
19   # . . . . . O . . . . . # # . O O O O   19
18   # . . . . . O . . . . . . # # . O . .   18
17   # . . . . . O . . . . . . # . . . . .   17
16   # . . , . . O . . # # # # # . , . . .   16
15   O O O O O . O . . . . . . # . . . . .   15
14   O . O . . # . . . . . . . # . . . . .   14
13   O O . . # # # # # # . . O . # # # # #   13
12   O . . . . . # . . . . . O . # . # . .   12
11   O . . . . . . . . . . . O O . . # . .   11
10   O O O , . . . . . , . . . O . , . . .   10
9   O # # . . . . . . . . . . O . . . . .    9
8   . # . O O O O O . . . . . O . . O . .    8
7   # # O O . . O . . . . . # O . O O O O    7
6   O O O . . . O . . . . . # . . . . . .    6
5   . . O O O O . . . # # # # . . . . . .    5
4   . . . , . . # . . , . . . . . , . . .    4
3   # # # # . . # . . . . . . . . . . . .    3
2   . O . # . . # . . . . . . . . . . . .    2
1   O O # # # # # # # . O O O . . . # # #    1
A B C D E F G H J K L M N O P Q R S T

LEGAL MOVES CONNECT TO EXACTLY ONE STONE OF THE SAME COLOR
----------------------------------------------------------
In FIGURE E, points T18, P19, R9, and M12 are examples of legal
moves for white.  Each of these moves connects to exactly one white

ILLEGAL MOVES THAT DON'T CONNECT TO ANY STONES OF THE SAME COLOR
----------------------------------------------------------------
Points N4, J12, K8, and K2 are examples of illegal moves for white.
These moves don't connect to any white stones.

ILLEGAL MOVES THAT CONNECT TO 2 OR MORE STONES OF THE SAME COLOR
----------------------------------------------------------------
Points F15, G5, B14, and B12 in FIGURE E are examples of illegal
moves for white.  These moves are illegal for white because they each
connect to two or more white stones already on the board.

Point F15 for example is an illegal move for white because it connects
to two white stones; one white stone is directly to the left of point
F15 and the other is directly to the right of point F15.

Point B14 is an illegal move for white because it connects to four
white stones: above, below, to the left, and to the right of point B14.

ROOTS
-----
By adding stones in this manner, the players form "roots" (A root is a
group of interconnected stones of the same color.)  In FIGURE B, roots
are just beginning to form.  As the roots grow larger, they compete
for limited growing space.

In FIGURE C, there are still 16 roots on the board.  After a few
games, players can easily discern the individual roots.

When a single root becomes so constricted that it can no longer grow,
the entire root is immediately removed from the board.  The
surrounding roots can then grow into the area vacated by the removed
root.  (Sometimes two or more roots will run out of growing space
simultaneously.  This is discussed separately, in detail below.)

In FIGURE D, white has won the game by eliminating the eight black
roots.  (See OBJECT OF THE GAME.)

FIGURE F: IMPOSSIBLE FORMATIONS
A B C D E F G H J K L M N O P Q R S T
19   # # # . # # # # # # . . . . . . . O O   19
18   . # # . . . . # . . . . . . . . O O .   18
17   . . # . . . . . . . . . . . . O O . .   17
16   . . # , . . . . . , . . . . O O . . .   16
15   . . # . . O O O O . . . . O O . . . .   15
14   . # # . . . . . O . . . O O . . . . .   14
13   O O O . # # . . O . . . O O . . # # #   13
12   O O O . # . . . O . . . . . . . # . #   12
11   O . # # # . O O O . . . . . . . # . #   11
10   # # # , # . . . . , . . . . . , # # #   10
9   # . . . # . O O O O . . . . . . . . .    9
8   # . . . # . O . O . . . . . . . . . .    8
7   # # # # # . O O O . . . . . . . O O O    7
6   . . . . . O O . . . . . . . . . O O O    6
5   . . . . . . . . . . . . . . . . . . .    5
4   . . . , # # # # . , . . O . # # # . .    4
3   . . . . . . # # . O O O O . # # # . O    3
2   O O . . . . # . . . . O O . # . . . .    2
1   . O . . . . # . . . . . O . # # # # #    1
A B C D E F G H J K L M N O P Q R S T

IMPOSSIBLE FORMATIONS
---------------------
The rules for adding stones make it impossible for certain types of
formations to occur in Tanbo.  In particular, separate roots of the
same color will never be joined.  Roots will not form closed loops or
clumps.  Every root will contain one of the stones of the initial
configuration (shown in FIGURE A).  New roots will never be created
during the course of the game.

All of the formations in FIGURE F are impossible.  They cannot be
created without violating the rules of Tanbo.

THE EXPANDED ROOT
-----------------
When a player makes a move, he connects his newly added stone to only
one of his roots.  This root increases in size by one and is referred
to as the "expanded root" during the player's turn.

The "expanded root" concept is essential to an understanding of the
following sections.

ROOT SPACE
----------
The "root space" of a root consists of the available legal moves
which serve to expand that root.  A root is "free" if it has at least
one point of root space.  For example, in FIGURE E, point D9 is the
only point of root space for the small black root.  Because that root
has root space, it is free.

BOUNDED ROOTS
-------------
A root becomes "bounded" when a move is made which completely deprives
that root of root space.  For example, in FIGURE E, if white adds a
stone to point D9, white deprives the small black root of root space,
therefore bounding it.

Alternatively, white could bound one of his own roots by moving to
point C2 in FIGURE E.  Expanding this small white root would leave it
with no root space, therefore bounding it.

The "bounded root" concept is central to Tanbo.

REMOVING BOUNDED ROOTS
----------------------
When a player makes a move which causes one or more roots to become
bounded, he will be required to remove at least one of these bounded
roots from the board, during his current turn. This is described in
detail in the following sections.

FIGURE G:                    FIGURE H:
ROOT IS EXPANDED             EXPANDED, BOUNDED ROOT
AND BOUNDED.                 IS REMOVED.
A B C D E F G H J              A B C D E F G H J
9   . O . O O # . . #   9      9   . O . O O # . . #   9
8   O O O O # # # # #   8      8   O O O O # # # # #   8
7   O . O . # . # . .   7      7   O . O . # . # . .   7
6   . O O O # . . # .   6      6   . O O O # . . # .   6
5   O O , O # # # # #   5      5   O O , O # # # # #   5
4   # # O O O O O O O   4      4   # # O O O O O O O   4
3   . # , # O # , . .   3      3   . # , # O # , . .   3
2   # # # # # # O O O   2      2   # # # # # # . . .   2
1   . # . . # O O .>O<  1      1   . # . . # . . . .   1
A B C D E F G H J              A B C D E F G H J

EXPANDED AND BOUNDED ROOT IS REMOVED FROM THE BOARD
---------------------------------------------------
If you make a move which expands and bounds one of your roots, you
must immediately remove this expanded and bounded root from the board.
FIGURES G and H demonstrate such a move on a 9 by 9 board.  By moving
to point J1 in FIGURE G, white expands and bounds the small white root
in the lower right corner.  White must immediately remove the expanded
and bounded root, as shown in FIGURE H.

FIGURE I:                    FIGURE J:
EXPANDED ROOT AND TWO        ONLY THE EXPANDED,
OTHER ROOTS ARE BOUNDED.     BOUNDED ROOT IS REMOVED.
A B C D E F G H J              A B C D E F G H J
9   O O # # . # # . .   9      9   . . # # . # # . .   9
8   . O O # . . # # #   8      8   . . . # . . # # #   8
7   O . O # # # , # .   7      7   . . , # # # , # .   7&127;
6   O O O O O # # # #   6      6   . . . . . # # # #   6
5   # # #>O<, O O O O   5      5   # # # . , O O O O   5
4   . . # . O O # O .   4      4   . . # . O O # O .   4
3   # . # # # # # O .   3      3   # . # # # # # O .   3
2   # # # . O O O O O   2      2   # # # . O O O O O   2
1   # O O O O . O . O   1      1   # O O O O . O . O   1
A B C D E F G H J              A B C D E F G H J

REMOVE ONLY THE EXPANDED, BOUNDED ROOT - NO OTHER ROOTS
-------------------------------------------------------
If your move expands and bounds one of your roots, and simultaneously
bounds one or more additional roots of either color, you must
immediately remove the expanded root, and only the expanded root.
become free again when you remove the expanded root.

FIGURES I and J demonstrate such a move.  By moving to point D5 in
FIGURE I, white expands the white root in the upper left corner.  This
move simultaneously bounds three roots: the expanded root, the black
root in the lower left corner, and the white root in the lower right
corner.  White must immediately remove the expanded root, and only the
expanded root, as shown in FIGURE J.

Two roots in FIGURE J, which were momentarily bounded during white's
turn, became free again when white removed the expanded, bounded root.
The white root in the lower right corner reclaimed its one point of
root space.  The black root in the lower left corner gained a few
points of root space.

At the conclusion of a turn, there should not be any bounded roots on
the board.

FIGURE K:                    FIGURE L:
EXPANDED ROOT IS NOT         REMOVE THE TWO
BOUNDED, BUT TWO OTHER       BOUNDED ROOTS.
ROOTS ARE BOUNDED.
A B C D E F G H J              A B C D E F G H J
9   O O # # . . # . .   9      9   O O # # . . # . .   9
8   . O O # . . # # #   8      8   . O O # . . # # #   8
7   . . O # # # , # .   7      7   . . O # # # , # .   7
6   O O O O O # # # #   6      6   O O O O O # # # #   6
5   # # #>O<, O O O O   5      5   . . , O , . , . .   5
4   . . # . O O # O .   4      4   . . . . . . . . .   4
3   # . # # # # # O .   3      3   . . , . , . , . .   3
2   # # # . O O O O O   2      2   . . . . . . . . .   2
1   # O O O O . O . O   1      1   . . . . . . . . .   1
A B C D E F G H J              A B C D E F G H J

IF ONE OR MORE ROOTS GET BOUNDED, AND THE EXPANDED ROOT IS
----------------------------------------------------------
NOT ONE OF THE BOUNDED ROOTS, REMOVE ALL THE BOUNDED ROOTS.
-----------------------------------------------------------
If you move to bound one or more roots of either or both colors, and
the expanded root is not one of the bounded roots, you must
immediately remove all of the roots which you bounded by making that
move.

By moving to point D5 in FIGURE K, white expands the root in the upper
left corner, and the expanded root is not bounded.  However, two other
roots are bounded by this move: the black root in the lower left
corner, and the white root in the lower right corner.  White must
immediately remove the two bounded roots, as shown in FIGURE L.

SUMMARY - WHEN TO REMOVE ROOTS
------------------------------
In summary, whenever a move causes a single root to be bounded, that
root is immediately removed.  When a player's move causes two or more
roots to be simultaneously bounded, the player must look at the
expanded root.

If the expanded root is one of the bounded roots, then the expanded
root, and only the expanded root is removed.

Otherwise, if the expanded root is not one of the bounded roots, then
all of the bounded roots must be removed.

The rules for removing roots were designed to ensure that when all
eight of a player's roots have been eliminated, the other player will
still have at least one root remaining on the board.  This prevents
ties from occuring.

RETURN OPPOSING ROOTS TO OPPONENT
---------------------------------
Whenever you remove an opposing root from the board, you must return
its stones to your opponent.  Players never take ownership of opposing
stones.  After stones have been returned to their owner, they can be
played again during later turns.

OBJECT OF THE GAME
------------------
To win, a player must eliminate all eight of his opponent's roots.
One player will always win.  It's impossible to repeat a board
configuration in Tanbo.  Therefore a game cannot result in a draw.

FIGURE M:                    FIGURE N:
LAST MOVE OF THE GAME.       WHITE HAS WON THE GAME.
BLACK MUST SACRIFICE
HIS LAST REMAINING ROOT.
A B C D E F G H J              A B C D E F G H J
9   O O # # . # # .>#<  9      9   O O . . . . . . .   9
8   . O O # . . # # #   8      8   . O O . . . . . .   8
7   O . O # # # , # .   7      7   O . O . , . , . .   7
6   O O O O O # # # #   6      6   O O O O O . . . .   6
5   O . , O , . # . .   5      5   O . , O , . , . .   5
4   O O . O O O # # #   4      4   O O . O O O . . .   4
3   O . , . O # # . #   3      3   O . , . O . , . .   3
2   O . . . O . # . #   2      2   O . . . O . . . .   2
1   O . . . O # # # .   1      1   O . . . O . . . .   1
A B C D E F G H J              A B C D E F G H J

FIGURES M and N show the last turn of a game.  In FIGURE M, each
player has one root remaining on the board.  Black's only available
move is point J9, and point J9 is also the black root's only remaining
point of root space. By moving to point J9, black bounds his last
remaining root which he immediately removes from the board, as shown
in FIGURE N. White has won the game.

FIGURE O:
A B C D E F G H J
9   . . . . . . . . .   9
8   . O . . . . . # .   8
7   . . , . , . , . .   7
6   . . . . . . . . .   6
5   . . , . , . , . .   5
4   . . . . . . . . .   4
3   . . , . , . , . .   3
2   . # . . . . . O .   2
1   . . . . . . . . .   1
A B C D E F G H J

BEGINNERS CAN USE A 9 BY 9 BOARD
--------------------------------
Beginners can play Tanbo on a 9 by 9 board with the initial setup
shown in FIGURE O.  After a few games, players will easily distinguish
one root from another.  And they will keep track of how much root
space each root has available.  Players should advance to the
tournament size, 19 by 19 board at this point.

III  THREE DIMENSIONAL TANBO
============================

The rules of 3D Tanbo are exactly the same as the rules of 2D Tanbo,
except it's played in three dimensions instead of two.

For example:

1. To make a move, you must connect a new stone to exactly one
stone already on (in) the board.

2. The expanded root will kill all of the roots it bounds, unless
the expanded root is itself bounded.  In this case, only the
expanded root is removed.

The following diagram shows the 5x5x5 cube that is tanbo3d.
Players express their moves as "XYZ" coordinates.  For example, the
center point of the cube is 333.
Z
tanbo3d game: 100   rrognlie (black #) vs mr.tan (white O)
_____________ _____________ _____________ _____________
/|            /|            /|            /|            /
/  |          /  |          /  |          /  |          /  5
/  O |        /  O |        / `O'|        /  . |        /  # 4
/  . . |      /  . . |      /  . . |      /  . . |      /  . . 3
/  # . . |    / {#}. . |    /  . . . |    /  . . . |    /  . . . 2
/  # . . . |  /  . . . . |  /  . . . . |  /  . . . . |  /  . . . . 1
| # . , . # |_| . . , . . |_| . . , . . |_| . . , . . |_| O . , . O
| . . . .  /  | . . . .  /  | . . . .  /  | . . . .  /  | . . . .  /
| . . .  /    | . . .  /    | . . .  /    | . . .  /    | . . .  /5
| . .  /      | . .  /      | . .  /      | . .  /      | . .  /4
| O  /        | .  /        | .  /        | .  /        | #  /3
|  /          |  /          |  /          |  /          |  /2
1/____________2/____________3/____________4/____________5/1     _____X
Recent Moves    Moves    Stones     Roots
#   O     #   O     #   O     #   O          /
--- ---   --- ---   --- ---   --- ---       -Y
125 255     3   2     7   6     4   4
135 355
235

IV  OTHER DIMENSIONS
====================

The lowest dimension that makes any sense at all for Tanbo is one:

# . . . . . O . . . . . # . . . . . O . . . . . # . . . . . O

The more dimensions you have, the more complex the gameplay becomes.

With a 19x19 board, the complexity is somewhere in the general
neighborhood of Chess and Go.  5x5x5 gameplay seems tremendously
complex to me, although I don't have the experience with it to say
for sure.

Although we can only visualize three dimensions, it is possible to
"conceptualize" four dimensions.  You can view a series of three-
dimensional "cross-sections" of four-dimensional Tanbo.  Computers
of the future may have hours of fun playing eleven-dimensional Tanbo.

V  ORIGINS
==========

Tanbo (2D) was, of course, inspired by Go.  I  concentrated nearly
continuously for about three weeks, searching inner space for a new
game-playing mechanism.  The result was Tanbo.

I played Tanbo for a year and a half before releasing this document,
and I plan to keep playing for years to come.

Tanbo is a subtle game.  There's not a lot of capturing.  As with Go,
you must safety your groups and you must fight a series of territorial
battles.

The word tanbo means rice paddy in Japanese.  Tanbo is not a variant of
Go, but it was inspired by Go and is related to Go.  The Japanese made
Go what it is today (even though it was invented in China as Wei-Chi
around 2000 BC).  Hence the Japanese name.

My thanks to Hernan Contreras.  He discovered a bug in the initial set
of rules, and he plays Tanbo with me often.```