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CYRUS II
========

Playing is believing as far as this the ultimate chess playing sensation for the Sinclair Spectrum is 
concerned.

The many features of this superior version means it will beat all existing Sinclair Spectrum chess programs 
published.

• Variable level performance
• 1900 standard book opening
• Set pieces
• Problem solving

plus many, many more unique features....

From beginner through to tournament playing expert Cyrus II is the only chess program that should interest 
you.


Introduction

Cyrus II is a chess program to interest players of all levels. Its abilities range from almost 
instantaneous play suitable for a beginner, through to tournament-style play for chess experts. It offers 
a wide range of operating features, enabling you (for example) to take moves back, replay a game that is 
over, or set up special positions for problem-solving.

If you like, start up the program and find out by experiment how to use it. No harm can come, whatever key 
you press, and Cyrus will do its best to understand your intentions.


Loading the Program

Insert cassette in tape cassette recorder Mark 1 - type LOAD "" then press ENTER.
Mark II - Press ENTER to accept tape loader option.


Starting a Game

Inside the square at the bottom left-hand corner of the board, you will see a flashing white arrow. This 
is the marker, which is used for indicating your moves to the computer.

By means of the four "direction" keys (← ↓ ↑ →), you can move the marker around the chessboard to position 
it wherever you want. A quick key-press moves the marker one square in the direction indicated. If you 
hold the key down, the marker keeps on moving until it reaches the edge of the board, or the key is 
released.

If you are playing White, make your first move like this:

  (a) Place the marker on the square occupied by the piece you want to move (so that it points towards the 
      base of the piece).
  (b) Press the ENTER key and the marker stops flashing.
  (c) Press a "direction" key again; you will now see two markers. One is flashing, and responds to your 
      commands; the other one, pointing towards your piece, remains static.
  (d) Move the flashing marker to the square where you want the piece to go.
  (e) Press ENTER again.

Your move is now carried out, and Cyrus starts computing its reply.

You can make the program move first - if you want to play Black - by pressing M. In this case, before the 
game starts, you will probably want to invert the chessboard by pressing the I key.


Special Moves

A capture is made no differently from any other move - simply move your own piece to its destination 
square. The same goes for a pawn capture en passant.

In order to castle, make the move of the King, and the rook's move is made for you automatically.

If you advance one of your own pawns to the far end of the board, this pawn will repeatedly move back and 
forth until you tell the computer what piece you want in its place. Press Q, R, B or N according to 
whether you want a queen, rook, bishop or knight. (Other keys have the same effect as Q. When Cyrus 
promotes one of its own pawns, it always chooses a queen.)


Message Display

On the Board display, the word CYRUS or PLAYER at the top or bottom, shows whether the computer or the 
user is playing from this end of the board, and with which colour.

A clock reading is also displayed for each opponent, for example:

                        01:17:36

- meaning that the total thinking time so far used by this side is one hour, seventeen minutes and 
thirty-six seconds. By seeing which "clock" is going you can tell which side is to move next.

If you press the space bar, the screen changes to a different type of display. In place of the chessboard, 
you will see a record of the last few moves made and a list of the commands currently at your disposal.

Here is how moves are recorded. Each file (or vertical column of squares) is given a letter, viewed from 
the "White" side, the letters range from "a" (on the extreme left) to "h". Each rank (or horizontal row) 
is given a number, running from 1 (at White's end) to 8. Each square is designated by the letter of its 
file and the number of its rank. (So at the start of the game, the White king is on e1, the Black queen 
is on d8, etc.) A move by a pawn is recorded by simply naming the pawn's old and new squares. When any 
other piece moves, its initial letter (or N in the case of a knight) is inserted before the departure 
square.

Example:        1       e2-e4           d7-d5
                2       e4xd5           Ng8-f6
                3       Bf1-b5+

White has started by moving his pawn from e2 to e4 (i.e. the pawn in front of his king has gone two 
squares forward). Black has replied with a double advance of the pawn in front of his queen from d7 to d5. 
Then the White pawn has captured the Black one (a capture is indicated by "x"), and Black has brought out 
his knight from g8 to f6. On his third move, White has played his bishop from f1 to b5; the *+" sign shows 
that this move gives check.

White's moves are always listed on the left, Black's on the right. Castling (on the king's side or queen's 
side respectively) is denoted by "0-0" or "0-0-0".

Below the game-record, you will see either the word THINKING (if Cyrus is computing the next move) or else 
YOUR MOVE.

Lower down the screen, there is a list of the commands that are currently available, e.g: 

                        B - Back

- reminding you that by pressing the B key you can retract a move. The full list of commands should be 
clear to you once you have read the remaining sections of this manual.

To return from the message screen to the chessboard screen, press the space bar again.


Result of the Game

The message screen displays CHECKMATE or STALEMATE if such a situation has come about.

If Cyrus recognises that the same position (with the same side to move) has arisen three times, it 
announces a DRAW.

A draw is also announced if, over the space of 50 consecutive moves (played by one side and answered by 
the opponent), no piece has been captured and no pawn moved.

To signify the end of the game, one of the kings (that of the player whose opponent made the last move) 
repeatedly "flashes" on the chessboard display.


Interrupting the Computer

If you press the M key while Cyrus is computing its move, it will cut short its calculations and play the 
move assessed as best according to its analysis so far.

Notice that most of the special operating features described below (e.g. selection of the "level", 
retraction of moves, etc) will not work when it is the program's turn to move. By inducing a moving, you 
enable any of the features to be used.


New Game

You can begin a new game at any time, by pressing the G key. The screen then shows:

                        New?

To confirm your command, press Y. The starting position reappears, and both "clocks" are set back to zero.

Note that until you actually enter a move or start Cyrus computing, the previous game still remains in 
the computer's memory. You can return to any position in that game by using the F key.

If you have pressed G by accident, a key-press other than "Y" allows play to be resumed.


Levels of Playing Strength

There are various levels of skill on which Cyrus II may be instructed to play. Obviously, the program 
plays more strongly the more thinking time it has for its moves. The following table shows the approximate 
average time it takes for a move on Levels 1 - 9.
                        Level   Time
                        1       2 seconds
                        2       6 seconds
                        3       15 seconds
                        4       30 seconds
                        5       45 seconds
                        6       1 minute
                        7       2 minutes
                        8       3 minutes
                        9       3 minutes 30 seconds

There are also three further levels, called "adaptable", "infinite" and "problem".

When playing on the adaptable level, Cyrus aims to play at roughly the same rate as its opponent; it 
measures your thinking time over a series of moves, then speeds up or slows down as necessary.

When computing a move on the infinite level, Cyrus will normally carry on thinking until you tell it to 
move by pressing M. If you don't do this, the computer will not actually play a move unless:

        (a) it has a "book" move available (see below);
or      (b) it finds a forced mate, or completes as deep an analysis of the position as is within its
            capacity;
or      (c) there is only one legal move it can make.

On the problem level, the program searches for a way to force checkmate in 5 moves or less; for more 
details, see the section on "Chess Problems".

When you first set up the program, Cyrus is ready to play on Level 1. The current level can always be seen 
on the message display. You may change the level any time when it is your turn to move, by pressing the L 
key. A single key-press takes you one level higher. If you hold the key down, you will see the level 
constantly changing - after going up to Level 9, the screen shows ADAP, INF, PROB, and then Level 1, Level 
2 ... and so on.

When the level that you want is displayed, simply carry on playing. The program remains on the same level 
(even after a new game starts), until you change it again; you may do so as often as you like.


Changing Sides

If you press the M key when it is your turn to move, Cyrus will start computing a move for the side that 
you have been playing, and will expect you to take over the other side.

You can change sides like this as often as you like. When you do so, you will probably want to turn the 
chessboard round, so that you will still be playing "up the screen". To invert the board, press the I key.


Playing Both Sides

It's possible for you to play a series of moves for both White and Black. For example, you may want to 
enter the moves of an opening variation which interests you, to see how Cyrus handles the resulting 
position. To do this, press S followed by M (you will then see the word PLAYER at both sides of the 
chessboard screen). You can now enter moves for both sides in turn. When you want Cyrus to carry on 
playing, re-press the M key.

This "multi-move" feature enables two human opponents to play a game against each other with the screen 
display as their chessboard.


Demonstration

If you press the D key, both sides will be taken over by the program, as a demonstration game. (Then CYRUS 
will be displayed at both sides ends of the screen). After finishing a game, the program will pause for a 
few seconds and then begin a new one. To halt the demonstration, press M. Then, after the next move is 
made, you may continue the game against the computer.


Retracting and Replaying Moves

If you've played a move but then have second throughts about it, you can easily take it back. Wait for 
Cyrus to reply, or make it do so at once by pressing M. Then press B, and the program's move is retracted. 
A second press of this key retracts your own last move, and you may make another one in its place. A move 
can be taken back even when the program is displaying checkmate or a draw.

By pressing the B key repeatedly or holding it down, you can take back a whole series of moves by both 
sides (going right back to the start of the game if you want). Notice that if you take back one more move 
for White than for Black (or vice versa), you swap sides with the computer.

The F key ("forward") has the opposite effecf to the B key; it replays the move or moves that you have 
taken back. As one example of its use, suppose that during a game you want to have another look at a 
position which arose 10 moves earlier. Take back the 10 moves with the B key; then, after you have 
finished examining this position, hold down the F key until you arrive again at the position where you 
interrupted the game. Play can now be resumed.

You can retract and replay the same sequence of moves as many times as you like. You may also carry on 
playing from any position within the sequence. This means you can find out what would have happened if 
you had played differently at a particular stage of the game.

Note, however, that when - in any position - you enter a new move or press M (or D) you are erasing from 
the computer's memory the moves that had previously been played from this position onwards. Those moves 
can no longer be replayed with the F key.

To review the entire game, you can press the G key and Y key (so that the starting position reappears), 
then repeatedly press F. This is not, however, possible if the game began from a position which you 
"set up".


Hint

If you want Cyrus to suggest a move for you, press H. One of your pieces makes a move on the board, and 
then goes back again. It is for you to decide whether to act on this hint; it is not necessarily the best 
move available (especially on the program's lower levels), though Cyrus will not deliberately mislead you.

If you press H when Cyrus is computing the next move, one of the program's pieces is moved back and forth 
in the same way. This shows you what move was rated as best at the outset of the analysis.


Analysis

If you would like some further insight into the program's train of thought, press the A key. The word 
ANALYSIS appears on the message screen. If Cyrus has just started computing its move, the display will
now remain unchanged for a few moments, but after that a series of moves will be recorded just above the 
list of commands. The first move in this series is the one that Cyrus is thinking of playing next -the 
best move according to its analysis so far. The following move is your expected reply, then comes the 
computer's intended answer to that... and so on.

For this feature, a simplified form of notation is used-each move is indicated merely by giving the old 
and new squares of the piece. The analysis display can be cancelled by re-pressing the A key.


Setting up a Position

Now and again you may want to see Cyrus solve a chess problem; or you may wish to set up a position from 
a game that has been published, to see how the program handles it. In order to rearrange the position on 
the chessboard, first press the S key. The wording SET UP appears on the chessboard screen, to show that 
the program is ready for a special mode of operation. Notice the new list of commands on the message 
screen - in "set up position" mode, some of the keys have different uses from their normal ones.

As long as SET UP is displayed, you can do any of the following things:

  (a) You can clear the entire chessboard by pressing C. Usually you will want to do this before anything 
      else - but not if the position that you intend to set up differs only slightly from the position 
      currently displayed.
  (b) To clear an individual square, position the marker on that square and press E.
  (c) To insert a piece on the board, bring the marker onto the desired square and press the appropriate 
      key: K (king), Q (queen), R (rook), B (bishop), N (knight) or P (pawn). The way to select the colour 
      of the piece will be explained presently.
  (d) Both of the clock times can be sent back to zero by pressing Z. (Notice that as long as the program 
      is in "set up position" mode, the clocks are stopped).

On the screen you will see the word WHITE or BLACK. This shows which colour a new piece will be, if you 
now place one on the board. To change over from one colour to the other, press X.

The word WHITE or BLACK also indicates which side will move next if play is commenced at this moment. So 
once the position is ready, you may need to press X to display the correct colour.

Finally press the S key, to take the program out of "set up position" mode again. The normal list of 
commands will now be shown on the message screen, and play may proceed.

Here's an example of how a position is set up. We'll suppose that the position you want is the following, 
and that White is to move.

Press S                 "SETUP" appears on the chessboard screen.
Press C                 The board is cleared.

If the word BLACK is displayed, press X (message: WHITE). You can now place White pieces on the board.
Bring the marker onto the square where you want the White king (b2)

Press K                 A White king appears.

Bring the marker onto the square for the White pawn (b3).

Press P                 A White pawn appears.

Bring the marker onto the square for the White queen (c4).

Press Q                 A White queen appears.

Press X                 The word BLACK appears. You can now enter black pieces.

Bring the marker onto the square for the Black king (f6).

Press K                 A Black king appears.

Bring the marker onto the square for the Black queen (g5).

Press Q                 A Black queen appears.

Press the X key (message: WHITE). Cyrus now knows that when play continues from this position, it will be 
White to move next.

Finally, press S. The word SET UP disappears, and YOUR MOVE is shown on the message screen. Play can now 
begin. Adjust the "level", if you want; then press M, to start Cyrus computing. (Or else, if you are 
playing White yourself, make a move in the usual way.)

In connection with setting up positions, there are a few more points to be noted:

  (a) Illegal positions: If you've set up a position in which (say) there are no kings, or one side has 
      two queens as well as eight pawns, or Black's king is in check when White is to move-then Cyrus 
      recognises this position as illegal. With such a position on the board, it is impossible to take 
      the program out of "set up position" mode and continue playing; when you press S, the computer will 
      merely give the "error buzz" and display ILLEGAL SETUP. Correct the position as necessary.
  (b) Castling: If a king or rook has been placed on the board in the way we have just described, there 
      can be no castling with that piece. A position in which (say) White has the right to castle King's 
      side may be set up as follows. First press G and Y (the starting position appears), then enter "set 
      up position" mode by pressing S. The White king and King's rook should now be left alone, while 
      unwanted pieces are removed individually with the E key.
  (c) En passant captures: After a position has been set up, the next move cannot be a pawn capture en 
      passant. To create a position where such a capture is legal, set up the immediatley preceding 
      position and then make the move which permits the capture.
  (d) Game record: When play proceeds after you have set a position up, the numbering of subsequent moves 
      always begins from 10. The computer's memory of any game you had previously been playing is now 
      erased.

This does not, however, mean that the foregoing moves are erased from memory if you press S by accident 
in the middle of a game. As long as you repress the same key without actually having made any alterations 
to the position, play may continue as before. The numbering of the moves remains unchanged, and if you 
like they can be "taken back" or "replayed" in the normal way.


Chess Problems

Most chess problems carry some such wording as "White to play and mate in three moves" - meaning that you 
have to find a move which enables White to give checkmate on this third move at the latest, no matter how 
Black tries to defend himself.

Cyrus II can solve problems for mate in anything up to 5 moves. Set up the position as described in the 
preceding section. Make sure Cyrus knows which side moves next. Select "problem" level with the L key. On 
leaving "set up position" mode, press M to start Cyrus computing.

Cyrus now begins by looking for a move that gives checkmate immediately. If it discovers that this is not 
possible, it displays NO MATE IN 1 on the message screen, and starts searching for a way to force mate in 
two moves... and so on. If the program finds (say) a forced mate in 3 moves, it momentarily displays MATE 
IN 3, and makes the appropriate move on the chessboard. You may now make a move for the defending side. 
Then (after re-computing if necessary), Cyrus will play the next move of the solution. After that, you 
can, if you like, take back the last pair of moves and play a different move for the defence, to see how 
the program answers it.

If Cyrus discovers, by performing an exhaustive analysis of the position, that it is impossible to force 
checkmate within 5 moves, it displays NO MATE IN 5, and simply makes the move it considers best.

NB: (a) If there is a "book" move available, Cyrus will move immediately, without performing any analysis.
    (b) Cyrus cannot solve problems that require "underpromoting" a pawn to rook, bishop to knight.


Saving and Loading Games

The record of a game may be saved on cassette, and later re-loaded into the computer for resumption of 
play, or for replay and analysis, etc.

When you want to use the cassette recorder, press the C key. You then have the following options.

  (a) To save a record of the game you have been playing, press S. The computer then prompts you to give 
      the game a name (for instance FIRSTGAME); this can be up to 10 characters long (it cannot contain 
      blank spaces). Type the name, and follow with ENTER. Press the PLAY and RECORD controls on the tape 
      recorder, then press any of the computer's keys. This will begin the saving process; once it is 
      finished, the program reverts to normal playing conditions (message: YOUR MOVE).
  (b) To load a game from cassette, make sure the tape is wound back far enough, and press L. Type the 
      name under which the game was recorded, press ENTER and the PLAY control, then press any key on the 
      keyboard. When loading is complete, the position that had been reached when the game was saved can 
      be viewed on the chessboard screen, and you may make use of any of the program's functions.
  (c) To allow play to be resumed (if, say, you pressed the C key by mistake), press any key other than 
      S or L.

If you make a mistake when entering the name of a game record, the DELETE key erases the last character 
typed. Note that the BREAK key and the space bar have the effect of interrupting any cassette operation 
and returning the program to normal playing conditions.


Printer

If you have a printer connected, pressing the P key allows you to operate it. This key-press automatically 
switches to the message screen, which displays a special menu of commands. You have these possibilities:

  (a) Press Z or P, according to whether you are using a ZX or serial printer. An asterisk on the screen 
      shows which alternative has been selected. Until you have done this, nothing can be printed.
  (b) For a print-out of the game-record up to the current position, press B. (The initial position of the 
      record is printed first.)
  (c) Pressing B causes the current position on the board to be printed.
  (d) Press C for a continuous listing of moves. This means that when play continues, each move will be 
      printed out as soon as it is made. An asterisk shows that this feature has been selected; to cancel 
      it, repeat the same command.
  (e) For further options, press 0. This enables you to set the baud rate for serial printing, by pressing 
      a key in the range 1 - 9. A table of baud rates and the corresponding key-presses is displayed on 
      the screen. In addition, the facility of inserting a "line feed" with each "carriage return" can be 
      switched on or off by pressing L.

Pressing a key not currently listed on the message screen has the effect of returning, from the special 
options under (e), to the main printer "menu"; or from there, to normal playing conditions.


Summary of Commands

A       Display analysis (predicted continuation). Repeat to cancel.
B       Take back last move; promote pawn to bishop.
C       Cassette operation.
        L  Load game record.
        S  Save game record.
        (Other keys: return to normal playing mode).
D       Demonstration (program  plays both sides).
F       Step forward, i.e. replay move taken back.
G       New game.
        Y Yes (Other keys: no.)
H       If user to move, give hint; if program to move, show move currently assessed as best. 
I       Invert chessboard.
L       Change level.
M       Take over the side which is to move; if already on this side, move immediately.
N       Promote pawn to knight.
P       Printer operation.
        B  Print board position.
        C  Continuous listing (each move printed when played). Repeat to cancel.
        G  Print game record.
        O  Further options (set baud rate; select carriage return + line feed).
        P  Serial printer.
        Z  ZX Printer.
        (Other keys: return to normal playing mode.)
Q       Promote pawn to queen.
R       Promote pawn to rook.
S       Selects "Set up" mode.
        B  Bishop.
        C  Clear chessboard.
        E  Empty square.
        K  King.
        M  Multi-move mode (user plays both sides).
        N  Knight.
        P  Pawn.
        Q  Queen.
        R  Rook.
        S  Return to normal playing mode.
        X  Change colour of pieces to be entered and side to move.
        Z  Set both clocks to zero.
ENTER   During move entry, selects square of departure or destination.
SPACE   Switch between chessboard and message screen.
↑↓←→    Move marker in direction indicated.
1-9     Move marker to specified rank.
CS+A-H  Move marker to specified file.


© 1986 Intelligent Chess Software Ltd. All rights reserved.
Unauthorised copying, lending, broadcasting or resale by any means strictly prohibited.
Alligata Software Ltd., 10range Street, Sheffield S14DW.Tel: (0742) 755796