by Tim Grice
 

Who Can Play	Chess Modifiers	Playing Procedure	The Strategies	A Sample Game
Gaining Chess Experience	Cheating	NPC Chess Players	Dragon 70	Dragon

The game of chess has its origins in
the distant past. In medieval times it was
known as the game of kings. Given the
quasi-medieval setting of most AD&D™
game environments, it seems not implausible
that knowledge of chess lurks
somewhere in the land. This article
demonstrates how to simulate the game
of chess in a fashion that is both reasonably
accurate and playable.

Who can play

For the purpose of simplicity, chess is
treated as a language insofar as learning
it is concerned. This means a character
must have an intelligence of at least
eight to be able to learn and play the
game. A character with an intelligence of
eight can know one additional language,
as indicated in the PH. If
the character in question chooses to
know how to play chess, he or she has
used up that additional language. A
character with an intelligence of 10, who
can normally know two additional languages,
can know only one additional
language if he or she chooses to know
how to play the game of kings. While the
game is treated as a language for learning
purposes, it should be remembered
that chess is not literally a language; just
because a character knows how to play
chess does not mean that character can
converse with any monster that can also
play chess. The character could engage
the monster in a game of chess, but any
other, more meaningful communication
between them is impossible unless both
have some spoken/written language in
common.

Chess modifiers

Not all chess players are created equal.
The degree of proficiency a chess player
has is simulated with a statistic called the
Chess Modifier (CM). When a person
learns the game his CM is low, but it will
increase as the player gains experience
in the game. Chess Modifiers range from
9½, for the lowest-ranked beginner, to
more than 100, attainable only by chess
masters: the average CM for a player
character is about 35. The basic Chess
Modifier for a character who has just
learned how to play chess is computed
by adding the character’s intelligence
score and half his or her wisdom score,
retaining the fraction if there is one. A
cleric with an intelligence of 11 and a
wisdom of 13 has a CM of 17½ when he
first learns the game of kings. When playing
the game his CM is considered to be
17 (dropping the fraction). The “extra”
fraction is used when the cleric gets better
at chess, as detailed below on the
subject of experience.

Playing procedure
The game of kings is played in turns,
each of which are, coincidentally, exactly
one turn (10 melee rounds) long. To prepare
for a game, the judge (DM) first
determines the Stalemate Limit for that
game by adding the players’ Chess Modifiers,
dividing that total by 10 (dropping
the fraction, if any) and adding the result
of a roll of d6. If the game continues for
this number of turns, it is considered to
end in a stalemate or draw, with no victory
for either player.

To begin each turn of a game of chess,
each player secretly chooses which of
the six strategies he will use and writes it
on a note which is given to the judge
(DM). Also on this note is the means, if
any, by which the player is cheating. The
judge then rolls percentile dice and modifies
the result according to the players’
strategies, according to whatever means
(if any) of cheating are being used, and
according to the players’ Chess Modifiers.
(The procedure is clearly outlined
later in this article by an example.)
Finally, the adjusted dice roll is used to
refer to the appropriate line on the Turn
Result Table (below), and the result read
from that table is used to adjust the
game’s cumulative score, which is set to
zero at the beginning of the game. If the
cumulative score reaches -4 at the end of
a turn, the game is over with a crushing
victory for White; a cumulative score of
-3 indicates a win for white; a cumulative
score of +3 indicates a win for Black; and

a cumulative score of +4 is a crushing
victory for Black. If the cumulative score
at the end of a turn is between -2 and +2
inclusive, the game continues until a
winner emerges or until the Stalemate
Limit for that game is reached.

Turn Result Table

01—05	Great move for White; adjust cumulative score by -2
06—45	Good move for White; adjust cumulative score by -1
46—55	No change in status; no adjustment to cumulative score
56—95	Good move for Black; adjust cumulative score by +1
96—00	Great move for Black; adjust cumulative score by +2

The strategies
The six strategies are: General Attack,
Build Up Own Position, Destroy Foe’s
Position, Set a Trap, Trade Down, and
Attack Foe’s King. At the beginning of
each turn Black and White both select
one of these, write it down on a note
(along with the method of cheating, if
any, being employed) and hand it to the
judge. The judge cross-indexes the two
strategies on the table below; this yields
a number, which is added to the percentile
dice roll generated by the judge.
(Adding a negative number is equivalent
to subtracting that amount if it were
expressed as a positive number.) Black’s
CM is added to, and White’s CM is subtracted
from, the resulting number. This
modified number (perhaps also further
modified for cheating; see that section in
the following text) is compared to the
Turn Result Table to determine the result
of that turn’s moves. Note that each
“turn,” for purposes of adapting chess to
the AD&D game, may represent more
than a single pair of moves on the chessboard;
what is being measured by the
Strategy Table and the Turn Result Table
is not necessarily the result of individual
moves, but the result of the application
of a general strategy over a series of
such moves, all of which constitute one
“turn” in the AD&D time system.

STRATEGY TABLE
A = General Attack; B = Build Up Own Position; C = Destroy Foe’s Position;
D = Set a Trap; E = Trade Down; F = Attack Foe’s King.
 
 

-	-	-	Black's Strategy	-	-	-
White's Strategy	A	B	C	D	E	F
A	0	-20	+10	+20	0	-10
B	+20	0	0	-30	+10	+10
C	-10	0	0	+20	-10	-10
D	-20	+30	-20	0	+20	-10
E	0	-10	+10	-20	0	+20
F	+10	-10	+10	+10	-20	0

A sample game
The cumulative score is set to zero.
White has a CM of 29. Black has a CM of
20. Black’s CM + White’s CM divided by
10 (drop the fraction) equals 4, which
means if the game is not won in 4 + 1-6
turns it will be a stalemate or draw. The
judge rolls d6, getting a result of 3, making
the Stalemate Limit for this game
seven turns. (The judge, of course, does
not tell the players how long they have to
play.) The players select their opening

strategies and give the judge notes telling
what they will do on the first turn.
Black will try to destroy White’s position,
while White is immediately trying to
attack Black’s king. The two strategies
are cross-indexed on the Strategy Table,
giving a result of +10%, so 10 will be
added to the percentile dice roll. The
judge rolls 82, which is modified to 92.
Adding Black’s CM of 20 and subtracting
White’s CM of 29 (a procedure which will
yield the same result for each turn)

means that the roll is modified by another
-9, making the final result 83. The 83 is
compared to the proper line on the Turn
Result Table, showing that the actions
taken on this turn constitute a good
move (actually, a series of good moves)
for Black. The cumulative score is adjusted
by +1, from 0 to +1.

Turn two: On this turn, Black is willing
to trade down, while White is mounting a
general attack. The two strategies cancel
each other out. The judge’s percentile
dice roll of 77 is again modified by -9
for a result of 68, another good turn for
Black. The cumulative score of +1 is
adjusted by +1, to +2.

Turn three: White is setting a trap,
while Black is attacking White’s king.
The dice roll is 56, modified by -10 for
the players’ strategies and by -9 for the
difference in their CM’s, for a result of 37,
a good turn for White. The cumulative
score is adjusted by -1, down to +1.
Turn four: White is trading down while
Black is launching a general attack. The
dice roll is 48, adjusted by -9 for the players’
CM’s but not adjusted for the difference
in strategies, for a result of 39,
another good turn for White, which puts
the cumulative score back at 0.

Turn five: Black is trading down while
White is building up his position, yielding
a -30% modifier. The dice roll is 30,
and taking the modifiers into account,
the resulting number is -9 (considered
the same as a result of 01, the lowest
number obtainable on the Turn Result
Table). This turn was very good for
White, and the cumulative score is adjusted
by -2, going to -2.

Turn six: Black’s cause does not look
good. The best he can hope for is that the
Stalemate Limit die roll was relatively
low, since with a cumulative score of -2
with (at most) 5 turns to go he would
need 5 “good moves” or 3 “great moves”
to win. Since White is the more skillful
player, Black’s chance of getting the
needed moves is slim. He chooses to
attack White’s king, while White chooses
a general attack. The modifiers of -10
(for strategy) and -9 (for CM’s) is applied
to the dice roll of 20, yielding a result of 1
— another “great move” for White. (In
this case, Black would have had much
better chances if he had set a trap.) The
cumulative score is adjusted by -2 to -4
ending the game in a crushing victory for
White. If Black had survived this turn,
and also not lost in the next (seventh)
turn, the game would have been a
stalemate.

In this sample game, neither Black nor
White engaged in cheating. If either or
both had, the result might have been different.
(See the section on cheating in
the following text.)

Gaining chess experience
As a character plays chess and gets
better at it, his Chess Modifier can increase.
But not every game presents the

opportunity to learn, and some games
will obviously teach more than others.
The more difficult a foe is to beat, the
more experience can be gained by the
other player.

In AD&D game terms, experience may
be gained whenever a character wins a
game of chess without cheating. The
winner must roll less than his or her intelligence
on d20, success indicating that
the winner has learned something while
playing. If the roll is failed, then the character
in question has not learned anything
from the game. In no case can a
character learn anything from a game,
for purposes of increasing his or her CM,
if that character did not win the game.
If the roll vs. intelligence succeeds, the
character’s CM goes up by an amount
equal to the opponent’s CM divided by
the character’s CM. In the sample game
described earlier, White (CM of 29) beat
Black (CM of 20). Therefore, if White
rolls less than his intelligence on d20, his
CM will be increased by 20/29. Then, if
and when White gains another 9/29 (for
example, by beating someone with a CM
of 9), his CM will go up to 30. If, for
instance, White beats an opponent with
a CM of 14 and makes his intelligence
roll, he would have a CM of 30 plus 5/29,
which would be rounded down (for playing
purposes) to 30. The fraction would
be counted when making further calculations
to gain more experience. (Note
that it is possible for a player’s CM to
increase by one point or more as the
result of a single game, if the winner of
that game had a CM equal to or less than
his opponent.)

There are restrictions on how rapidly a
player character can gain chess experience,
regardless of how many games
the character wins in a span of time. The
NPC noble with little else to do but putter
around and think could conceivably increase
his CM by a substantial amount in
a single day. A player-character adventurer
will have many far more important
things to do than play chess all the time;
such a player’s CM cannot increase by
more than one point within a span of 1-4
weeks; the DM must roll d4 for each
player to determine his or her “learning
limit,” which will apply throughout the
player’s chess-playing lifetime. The only
exception to this one-point limit is for a
player who earns more than one CM
point in a single game, and in this case
that player is limited to the amount of
that increase for the next 1-4 weeks.
Another restriction is this: Only the
first game an adventurer plays against
someone has any chance of affecting the
adventurer’s CM. While this is not true in
the real world, in game terms it is utterly
necessary; otherwise, all the chess players
in a party could play each other over
and over again and gain chess experience
in round-robin fashion until all
had reached their maximum CM’s.

Each player’s Chess Modifier has an

upper limit, beyond which further progression
is impossible. The maximum
CM of a person (NPC) who has nothing
to do but play chess all day, every day, is
5 times his initial Chess Modifier (intelligence
+ half of wisdom). Player-character
adventurers, who cannot spend a
large amount of time on the game, can
never advance beyond 3 times their initial
Chess Modifier.

Cheating
Several methods of cheating at chess
exist in an AD&D context. A player attempting
to cheat must indicate that, and
specify the method being used, on the
note that he gives the judge at the beginning
of the turn. Being caught cheating
has many different possible consequences,
ranging from expulsion from the
game to decapitation, depending on who
does the catching. The Dungeon Master
must decide the severity of the punishment
on a case-by-case basis.

The simplest way to cheat is to try to
move the pieces around when no one is
watching. A player who succeeds at this
gains a bonus to his CM — for the current
turn only — equal to his dexterity. In
the game example given earlier, suppose
that Black (CM of 20) decides late in the
game that cheating is better than losing.
The cumulative score is -2, on turn six.
Black has a 14 dexterity. If he succeeds
in moving the chessmen around, his CM
for this turn will be 20 + 14 = 34.

Cheating in this fashion, however, is
not without risks. The player attempting
to cheat must make a roll of dexterity or
less on d20 for all those watching the
game (including his opponent and any
spectators, but not the judge). Each roll
that fails alerts one watcher. Thieves are
allowed two rolls per watcher, the first as
above and (if it fails) the second a percentile
roll with the same chance of success
the thief has of picking pockets.

This method of cheating can be tried
only once per turn. Each succeeding try
on later turns in the same game lessens
the necessary d20 roll by one, and lowers
the pocket-picking percent of a thief
by 5%; this sort of cheating becomes easier
to detect the more often it is tried. If
the player cheating has a dexterity of 20
or higher, or is a thief with a pick-pocket
percentage of 100% or more, there is still
a 1% chance of the cheating being noticed.
For this and all other methods of
cheating, the judge (DM) does the dicerolling,
to keep unknown the fact that a
cheating attempt is being made.

Another means of cheating, far harder
to detect, is through the use of ESP. The
medallion can be detected by a physical
search or by some form of detect magic,
and use of the spell can be revealed by
detect magic, but the psionic abilities of
ESP and telepathy can only be detected
by a psionic character, by the use of
ESP, or a detect lie spell. The ESP spell
can be cast on the sly by mumbling the

verbal component and moving the hands
in the Somatic fashion under the table. A
magic-user attempting to cast an ESP
spell surreptitiously must make a saving
throw of his intelligence or less on d20
for each watcher to avoid the casting
being detected.

If the spell is successfully cast or the
power successfully employed by a medallion
or through psionics, the effect of
ESP is devastating: For that turn the
opponent’s CM is lowered to zero, and
rather than the ESP -user having to select
a strategy, the most favorable one (from
the viewpoint of the ESP -user) is applied
against the opponent’s choice of strategy.
If both players are using ESP, that
turn of the game will have no result, with
no adjustment of the cumulative score,
and each player will be aware that the
other is cheating.

Use of the psionic ability of empathy is
almost undetectable (5% chance per turn
used, cumulative, and only detectable by
other psionic characters or those able to
detect the expenditure of psionic energy),
and results in the lowering of the
opponent’s CM to 2/3 of normal for the
turn in question.

When playing to lose (for whatever
reason), a player need not use all of his
CM. In fact, a player can use a negative
CM of up to 1/2 his normal Chess Modifier
without being obvious. (This desire
should be communicated to the judge in
the note preceding each turn.)

Far and away the most common form
of cheating is by intimidation. Whenever
intimidation is attempted, by whatever
means, the intended victim of the intimidation
must roll his wisdom or less on
d20 (adjusted up or down at the Dungeon
Master’s discretion, according to
the severity of the intimidation) to avoid
being intimidated. The effect of successful
intimidation is to lower the victim‘s
CM by 10% for one turn. This effect is
cumulative, to a maximum of five successful
attempts (a lowering of the CM
by 50%) in one turn.

Intimidation can be accomplished by a
multitude of means, including having
husky bodyguards breathing over the
victim’s shoulder, laughing whenever the
victim makes a move, “playfully” swishing
a sword in the victim’s direction, and
so on. Any particular form of intimidation
can only be attempted once per
turn, but can be tried turn after turn if so
desired. Whenever any player is competing
against a dragon who has more than
half the other player’s hit points, an
automatic possible intimidation takes
place, and the other player must make a
roll against wisdom or be intimidated.
Intimidation is semi-open; that is, it is
apparent to the intended victim and any
onlookers, and the players involved can
make their own rolls against wisdom. All
die rolls pertaining to other forms of
cheating are rolled in secret by the judge.
A player who cheats or attempts to
cheat can gain no experience from the
game in question. However, there may
obviously be other reasons for a player
to engage in a chess game and attempt

to cheat in order to enhance his chances
of victory; winning a bet on the outcome
of the game is perhaps the most obvious
of all.

NPC chess players
A non-player character’s chance of
having learned how to play chess is
dependent on the character’s profession
and intelligence. Remember that a character
must have an intelligence of at
least 8 to be able to play chess. NPC’s
who can play the game will have the
basic Chess Modifier of intelligence +
half of wisdom in addition to a bonus,
which is generated according to the following
list:
    Noble: Chance of knowing chess is 5% per point of intelligence, bonus to initial CM is 1-40.
    Magic-user: 3% per intelligence, 1-30
    Fighter: 2% per intelligence, 1-30
    Thief: 2% per intelligence, 1-40
    Cleric: 2% per intelligence, 1-10
    Gambler: 2% per intelligence, 1-50
    Merchant: 2% per intelligence, 1-20
    Serf: ½% per intelligence, 1-8
    Chess Master: 100%, 50 + 1-50
    Dragon: 1% per intelligence + ½% per hit point, 0-7 per age level
    Others: 1% per intelligence, 1-12
The CM bonuses and chance to know
the game are only for non-player characters.
Player characters must learn the
game from someone who knows it already,
and will have the initial Chess
Modifier of intelligence + half of wisdom
until gaining experience.

Chess compliment
 

Dear Editor:
I was very pleased to see Tim Grice’s article
on chess in DRAGON #70. Being perhaps the
highest-rated (2200+) United States Chess
Federation player who subscribes to the
magazine, I felt compelled to write.

In short, the article was superlative. The
plusses and minuses in the matrix were very
well thought out. The various methods of
cheating were interesting. Even the maximum
rate of assimilation of chess knowledge was
thought of, thereby making the system more
realistic.

I would suggest these modifications and
enhancements to the system:

1. Permit either player to play a gambit in
the opening. The gambitting player gains 10
points to his CM for 3 turns; however, he loses
10 points on his CM for the rest of the game
thereafter. If both players gambit, Black gains
15 to his CM for 3 turns, then loses 10 for the
remaining turns. (This is realistic. Gambitting
players are normally unable to handle the
psychological effects of a counter-gambit.)

2. Change the % chance to move pieces
(cheating) as follows: Must roll dex on d20
(one time only) to succeed; then, for each
observer, d% are rolled. Any roll less than or
equal to the observer’s or player’s CM indicates
that the cheating attempt was noticed.
(Let’s face it, you simply can’t move the pieces
on a master without his noticing the attempt.
This rule change incorporates that concept.)
If either of the dice rolls described above fails,
the attempt is unsuccessful. Once the cheater
is caught, further attempts are at a penalty
(-10 modifier to each observer’s dice roll,
cumulative per attempt).

3. Modify the intimidation “saving throw” by
+1 for each 10 points of CM. (1-10=+1,11-20=
+2, etc.) This change is suggested because
relatively good players are relatively less easily
intimidated.

4. In drawn games, player with lower CM
gains half the CM he would have gained if he
had won the game.

I hope these suggestions will make the
“game within a game” more realistic.

Jim Rousselle
New Orleans, La.
(Dragon #72)

Quote:
Originally Posted by Dannyalcatraz
Or Dangerous Journeys!

Side notes about chess & checkers:

1) The queen's full-board range of motion is a relatively new addition to the game.
Originally, she could only move 1 space at a time. The chess we're used to is like...14thEd Chess. I wonder if the original players ever got pissy about the changes?

One space on the diagonals, properly

The last change in the game of chess was castling added around the time of Ruy Lopez, possibly by thet very person, but I can't properly remember. It was in the 15th century IIRR.

Taking en passant came before castling.

Likely there were some who preferred the game without the new rules, but there is no real analogy between chess and the D&D game changes, unless one compares D&D to chess and the other games, AD&D and new D&D to chess variants.