------------------------------------------------------------------------ Detective Chess - Copyright 1996 by Gerry Quinn ------------------------------------------------------------------------ *This file may be read in Windows Notepad - set WordWrap on* ------------------------------------------------------------------------ Welcome to Detective Chess, a challenging puzzle game based on the rules of Chess. Detective Chess runs on any 386+ IBM-compatible PC running Windows 3.1+ or Windows 95. The current version is V1.0. Detective Chess is copyright but freely distributable. The shareware version requires a keyfile (which is *not* distributable) to activate many of its functions. However the unregistered version is still fully playable, just a bit limited in its options. ---------------------( INSTALLATION )---------------------------------- You will have received Detective Chess as a "zip" file named DETCHESS.ZIP. Make a new directory (folder) and copy the zip file into it. Unzip the file using File Manager or Explorer (or from DOS using Pkunzip). Several files will be created. Now run the program called DETCHESS.EXE (you must run it from Windows or Windows 95). It will request permission to install a program called DVServer on your system (unless this program is installed already). The process is reversible if at some time you wish to de-install. (If DVServer is not automatically installed by DETCHESS.EXE, try running DVServer directly instead.) You can now run DETCHESS from File Manager, or you can create a program item for it. It is suggested that you call it "Detective Chess" and place it in your "Games" program group. It should appear as an icon of a small chessboard with a question mark. (On some systems the graphics may not work properly the first time the program runs - if so, just quit and run it again.) ----------------------( PLAYING INSTRUCTIONS )------------------------- The purpose of the game is to guess the position of some pieces on a chessboard. In the unregistered version, these are always a King, Queen, Rook, Bishop and Knight (one of each). When the game loads, you will see five squares with blue borders on the chessboard, some numbers scattered on the chessboard, and a box containing the five pieces. The pieces should be placed on the five blue-bordered squares in such a way that every numbered square is attacked by exactly that number of pieces. If the number is zero, no piece must be attacking it. If it is one, then exactly one piece must be attacking it, no more and no less. There is only one solution. You can move the pieces using the mouse. Left click to pick up a piece or put it down. Press the button marked "Guess" when you think you have the solution. Or press "Give Up" if you think you will never get it! You might want to give up the first game just to make it clear to yourself what is going on. There is a "Help" button which gives extensive online help, including brief reminders of how the pieces move. Click on this, then go through all the buttons and menu items, and soon you will have a fair idea of what you can do. You can create a new position by selecting the appropriate menu item, or just by pressing F2. Detective Chess calculates a totally new random puzzle every time, so it will never run out of puzzles. ----------------( UNDERSTANDING THE MOUSE POINTER )--------------------- As you play, the mouse pointer changes to reflect what's going on: A Hand -> You can pick up a piece (this is called Move mode). A Piece -> You are carrying a piece; click on an empty square to put it down. A Question Mark -> You can click on an empty square to get the number of pieces attacking it (this is called Hint mode). A Pen -> You can write a short note on any square (this is called Write mode). Just click on the square, type your note, then press "Enter". The note is just a reminder to yourself. For example if you know a certain square must contain a King or a Rook, you may write "KR". The "Erase" button removes all notes. A Little Book -> You can click on any square, piece, button or menu item to get information (this is Help mode). An Hourglass -> The program is "thinking". An Arrow -> The pointer appears as an arrow when it is outside the game window, or in the menu or title area. The mode does not change from what it was previously. You can press the buttons "Write", "Hint", "Move" or "Help" to force the program into the appropriate mode at any time. These buttons also have hot keys: New game = F2 Write mode = F6 Hint mode = F7 Move mode = F8 Help mode = F1 You win the game by pressing "Guess" when all the pieces are correct. You will be told what's wrong with your guess if it is not correct. There is no limit on the number of guesses you can make. But of course you aim to have just one. On the menu are different versions of the game: The Standard Game (with which you always start). The Explorer Game (you are not given any numbered squares, but you can click on any square to get a number). Since you will need to start by getting a few numbers, this game starts up in Hint mode. The No-Clues Game (leave this till you are expert!). You are not even told which squares the pieces are on. Again you start off in Hint mode. If you are registered, you can change the pieces and make it a bit easier. The All-Numbers game (you are not shown the five squares the pieces are on, but on the other hand you are shown the attacks on every square on the board. A good way to refresh your memory on the way the pieces attack - select this game then press Give Up) ----------------------( GAME SETUP OPTIONS )---------------------------- Registered users can activate the Game Setup options (on the menu). If you haven't registered, you can only look! These options allow you to enormously increase the variety of puzzles which Detective Chess can make for you, and tailor them to your own level of skill. Whatever options you choose, they apply to each of the four game types. Here is the explanation of each option: Board Size: Well, this requires no explanation! Spread Out: When selected, the program will try to generate positions where the pieces are not clustered together, rather than completely random positions. It's purely a matter of taste. Fairy Pieces: When selected, the three fairy or non-standard pieces are activated and may be selected as well as, or instead of the five normal ones. Piece Numbers: The main part of the setup window is taken up by nine controls which allow you to change the number of pieces. There is an overall maximum of twenty pieces allowed, and you can select any combination which adds to twenty or less. You change the number of each type by clicking on the arrow squares. See the section entitled "Technical Notes" for limitations on the options selected for the standard game. On the left are the five standard pieces, King, Queen, Rook, Bishop and Knight. The default setup has exactly one of each. On the right are three fairy pieces and a questionmark. You can select fairy pieces only if you have checked the "Fairy Pieces" option. The pieces are (from top to bottom): The Grasshopper: moves in eight directions like a Queen, but can only move by jumping over a piece to the square immediately beyond. If we have a row of pieces like this: - - G - N * - - where N is a Knight and G is a Grasshopper, only the square marked * is attacked by the Grasshopper. It can only jump over a single piece. The Nightrider: an extended Knight - it attacks squares that are two steps across and one square up, four squares across and two squares up, and so on. It is blocked by a piece on its path of consecutive Knight hops. Thus the Knightrider is to the Knight what the Queen is to the King. The Maharajah combines the moves of Queen and Knight. All the fairy pieces are briefly described by the Help option when selected in the game during Help mode. Question Mark: When you select one or more question marks, each will be converted into a piece at random. The piece selected will differ from game to game. If the Fairy Pieces option is selected, then fairy pieces and/or normal pieces will be generated, otherwise just normal pieces. You can combine one or more question marks with any number of pieces, so long as the total does not exceed twenty. Okay: This quits game setup and goes back to the board: a new position will immediately be generated according to the options you chose. Default: This restores the default options. A new position is still generated. Cancel: Quits game setup without changing options. A new position is still generated. ----------------------( TECHNICAL NOTES )---------------------------- In the Explorer, No-Clues and All-Numbers games, the program does not have to do much in the way of calculation. It basically generates a position at random, shows certain clues, and responds to your mouse input. The number of pieces is completely immaterial to it. In the Standard game, matters are different. Not only must a random position be generated, but the program must be sure it has given you enough clues to solve it, and no more. It does this by a brute force method. Every possible permutation of the pieces on the marked squares is generated and compared with the true solution. The squares containing different attack numbers are recorded, and a small subset is selected, such that each square has a vital role in the solution. Where there are five different pieces, 120 positions must be generated. The number of positions rises exponentially with the number of pieces, but is less if some of the pieces are duplicates. It was necessary to set a limit on the number of positions evaluated, so that the process would finish in a reasonable time, even on a slow computer. The limit chosen, for this version anyway, was 12000. So the Standard game can only evaluate piece sets with a maximum of 12000 combinations. This could be: Seven different pieces: 5040 combinations Eight pieces containing two duplicate pairs: 10080 combinations (e.g. KQRBNNGG) Four Kings, Four Queens, Three Rooks: 11550 combinations Four of one piece and sixteen of another: 4845 combinations And so on... Anyway, you can have more pieces or more different types, not both. The board size has no effect on the number of combinations. The program will accept your instructions, whatever you choose, but if there are over 12000 combinations, it will eliminate pieces at random until it has a selection it can work with. Conversion of question marks to pieces takes place first, so if there are question marks both the number and type of pieces finally selected may change. If you select fifteen or so question marks, and normal pieces, most games will have eight or nine pieces. Of course, you could always select the Explorer game instead, and have precisely the combination of pieces that you want. -------------------( TIME TAKEN )-------------------------------------- On a fast Pentium, all positions are generated in a second or so. Slower machines will take a bit longer, depending on the number of combinations. It *won't* be 100 times as slow as the default setup, however, since most of the time used by the default is taken up by graphics rather than calculations. A 486/SX20 can take something like 10 seconds for a very complicated position. The program has been optimised for maximum speed on any machine. The presence or absence of a co-processor should not affect it appreciably. Board size has only a small effect. If five or more pieces are selected, a progress bar may appear during the calculation phase to show how the program is getting on. The program will only generate this bar if it thinks the calculation will take more than one second. One thing which can slow calculations is the possibility that the position will be ambiguous. Imagine a King hemmed into the corner - it now has the same attacks as a similarly blocked Queen. When the program cannot calculate a suitable set of attack numbers, it generates a new position and starts again, repeating as necessary until it has generated a well-formed puzzle. This only happens rarely under normal conditions - certain piece combinations and board sizes tend to be more prone to it. If you see the progress bar going back to the start, this is why! Explorer, No-Clues and All-Numbers games should be calculated almost instantly under all conditions. -------------------( REGISTRATION )------------------------------------ Registration of this game costs only £5, US$10, or DM15, if you register electronically. By this I mean that I send a personalised keyfile (containing fifty 5-digit numbers) to your email address (or a friend's). You save the file to a textfile in your Detective Chess directory, and the Game Setup functions will thenceforth be fully functional whenever you play. Electronic registration is fast and cheap. If you (or a friend) have the facility to save an email as a text file, you should register this way. I can also send the keyfile on floppy disk, but it costs extra for disks, jiffy bags, stamps and trouble. The price is £8, US$15, or DM25. (I program mainly for fun, but for licking stamps I charge the full hourly rate!) If you are willing to type in 250 digits exactly as printed, and you have access to a fax machine, I can send you a fax for the same price as electronic registration. Don't forget to include your email or fax number. You must also include your name and address even when registering by email, as these will be encoded in your keyfile. ---------------------( SENDING MONEY )--------------------------------- In a few years, you will probably be able to do this instantly and electronically. But for now, it will have to be the post. Credit card registration is not possible for me at the moment. You can send me cash: Sterling, Dollars, Deutschmarks or Punts. This is **AT YOUR OWN RISK**. But, due to my bargain-basement prices, you are not risking all that much. If it does not go astray in the post, this is the cheapest method of paying. If it does, the loss is yours! So wrap it well. Only notes rather than coins are acceptable; I make an exception for £8 Punts or Sterling, where I will accept a £5 note and £3 in coins. However, you can more safely send a personal cheque for Punts or Sterling. I can't take any other currencies in cheque form as the banks charge huge commissions. You can send a bank draft or international money order. This is the method generally recommended by the cautious, but you may well wonder whether the commission is worth the extra security for such a small amount. The choice is yours. Send your registration fee to: Gerry Quinn, 21 Forest Park, Drogheda, Co. Louth, Ireland Email: gerryq@indigo.ie Well, so much for filthy lucre! ---------------------( CONTACT ME! )-------------------------------- Whether you want to register or not, I would like to hear from you. Especially if you find bugs, large or small, or the game won't work on your system. Also, about any things that annoy you, any features you miss, any ideas you feel could be added, etc. Email me at: gerryq@indigo.ie I don't promise to upgrade Detective Chess except to fix bugs. However I don't rule it out, and enhanced versions may very well appear. If you register, your keyfile will continue to work on any future version. -----------------------( FINAL NOTES )----------------------------- I first came across a puzzle of this type in a book of puzzles by Isaac Asimov, although he did not invent them (apparently an Argentinian named Jaime Poniachik did). A couple of years ago I wrote a primitive version of this game for the Amiga (it only had the Explorer game, only 5 pieces, no special pieces etc.) It can be downloaded from: Aminet/game/think/voz-chess.lha (it's only 37K). -------------------------------------------------------------------