ZX Chess II

ZX Computing

John Cooper

READERS' REVIEWS Once more we open our pages to the people who use the programs the most - YOURSELVES! ARTIC CHESS II Artic Computing John Cooper The program comes neatly packaged in a cassette box with instructions on how to use the tape on the inlay card. There are two copies of ARTIC CHESS II on the tape - one on each side. The instructions are clear and to the point, so I had no problems using the program. Once loaded you are prompted to input P, A or L for PLAY, ANALYSE or LOAD. I decided to PLAY and was then offered a choice of colours (black or white) and a choice of levels to play on (0-6). Having decided to play white on level one, I was presented with a large chessboard with the pieces set up in the starting position. I entered 'E2 E4' and to my delight the pawn at E2 was moved up to 'E4'. The program is in full machine code, so I did not have to wait long for a reply (on this level it took one second). It is a good idea to have a chess set and board handy to start with until you get used to the screen display. On all levels except '0' the computer will recommend a move for you if you press 'M' except in the very early stages of a game. Other options are as follows: (1) 'T' saves the game on to tape (so it can be continued at a later date). (2) 'Z' copies the position onto a printer. (3) 'S' pressed at any time during the game will return you to the PLAY ANALYSE or LOAD prompt. This can be usefully used for resigning and going into ANALYSE mode in which you can place and delete pieces as you want. I have one major quibble here, playing on from the set-up position. You have to press 'Z', and then you have to enter a move depending on whether you are black or white before going into ANALYSE mode, only then does it ask you what colour you want to resume play as, and at what level you wish to play. Overall, this is a superb chess game for the ZX81 with 16K RAM which plays a strong game with varied openings and I would strongly recommend it to anyone who wants a good game of chess. ARTIC CHESS II is available from: Artic Computing, for £9.95.

Sinclair User

Quentin Heath

CHECKING THE BEST MOVES IN GROWING CHESS MARKET Quentin Heath emerges from the dungeons to return to the boards. In the last few months I have been stuck underground in the Sinclair User dungeons with a variety of man-eating monsters, so this month I thought I would seek some fresh air and talk about chess. In later articles I want o say something about the structure of chess programs but for now I will introduce you to what is available for Sinclair machines. Most of the early ZX-81 games were, more or less, copies of a famous American chess program called Sargon. Many manufacturers used the Sargon basic structure and re-wrote the printing routines so that they would be compatible for the ZX-81 screen format. After a few months of copying, manufacturers began to alter programs to make them play better and run faster. Out of the first batch of games to arrive on the scene, the Attic Computing ZX-81 Chess was acclaimed the best by the critics. The original Artic chess, and its upgraded version, Chess Two, have sold well and with good reason. The games include all legal moves, with castling and en passant, and can be played at six levels. The easiest level has a response time of about one second and the most difficult, level six, takes several minutes to make a move. Chess Two plays a good entertaining game for anyone with a slight knowledge of the laws of chess and when I played with it the game did not make an incorrect move, even on the simplest level. It is the game I would recommend for the average player who wants to try to beat a computer at chess. Some people may argue that a computer can play only a mechanical game with no invention or luck but playing a computer will give you some practice if no partner is available. Artic also produces a technically-excellent game which fits into the 1K ZX-81. It may not play brilliantly but it is fascinating to watch the computer scan the moves available to it graphically on the screen. The computer makes moves very quickly, although it will not allow the usual en passant and castling which are available on the bigger games. The game loads very quickly and at £2.95 it is worth the money. Artic has upgraded its ZX-81 chess games to the Spectrum. There are at present three versions but only one is for the 16K Spectrum. So far as I know it is the only chess program for the 16K machine. Its playing standard is similar to that of ZX Chess Two. The most interesting of the chess programs from Artic is Voice Chess. It not only plays as well as Spec Chess, the other game in the trio, but each move made is announced by a voice which is generated by the Spectrum loudspeaker. Some people have asked if the amount of memory used to store the voice affects the quality of the game. So far as I can tell, it does not do so noticeably. Most chess programs occupy a great deal less room than 48K and the voice is just filling the space which is not used. My own feeling is that if you want a game with novelty you should buy Voice Chess but if you just want to buy a good game with no frills, 48K Spec Chess and 16K Micro Chess are choices. Master Chess, from Mikro-Gen, also provides a formidable game. It runs on a 48K Spectrum and has 10 levels of play which are numbered from zero to nine. If you do not know which move to make the computer will suggest one for you. The game also includes an analysis option which can be used to solve chess puzzles. The Masterchess program is capable of all legal moves, including en passant and castling. To see how the games compete with a real chess machine I played a game between the Quicksilva Chess Player and a Sci-Sys chess computer. The results were interesting. Sci-Sys was slower in making moves than the Quicksilva game on level one but the dedicated chess computer earned checkmate in 67 moves. What was also interesting was that the Sci-Sys system often anticipated the moves of the Chess Player. That may indicate that most structures are similar. The final game I want to examine is the best available, in my opinion. Superchess Two is from CP Software and is a chess player's dream. The range of options includes 10 levels of play, a recommended move option, self-play, analyse and technical information. The self-play mode pits the computer against itself so that you can see how it solves game problems. You can also provide it with problems to analyse and solve. The most advanced level is level 10. At that level the computer can take several hours to make up its mind about a move. The game also includes an option which I have never seen in other chess programs. The technical information option will tell you how the program is structured and which techniques are used for the computer to find its next feasible move. Explanations of tree searches and data structures is provided to give the player a chance to further the computer's 'mind'.

ZX Computing

Nick Pearce

THE CHESS GIANTS GRAPPLE Sinclair Research is selling a chess program for the ZX81, developed by Psion/Microgen. Reviewer Nick Pearce tried it out, and played it off against Artic's Chess II. Originally I intended just to review the Psion program, as part of my review of the new Sinclair ZX81 software, but decided that a comparison with ZX Chess II by Artic, fast becoming the standard for ZX chess, would be more appropriate. The comparison, although interesting, is perhaps a little unfair. Chess II currently retails at £9.95, while the Psion program, together with CHESS CLOCK on the other side of the cassette, sells for £3.00 less. Both programs display the board on the screen, and pieces are represented by letters, K for King, Q for Queen, B for Bishop and so on, with the colour of the piece being the colour of the displayed letter, inverse letters for black pieces. Both games use the standard algebraic system of chess notation for the board co-ordinates, although the Artic program is the only one which actually puts these co-ordinates on the screen. The Artic board is always displayed the same way up, no matter which end the human is playing from, while the Psion board is shown with the player at the bottom. I feel this makes the Psion program rather easier to play. Although I expected to, I did not find the lack of co-ordinates on the screen a disadvantage, as I found with both programs it was only really possible to play a normal game by having a proper board set up beside the TV anyway. Both programs give you the option of setting up a game position. The Artic program requires you to set up a piece by first defining the co-ordinates, then entering a code for the piece you want there. On the Psion board, you use a cursor (=) to move pieces around the board. A deficiency with the Psion program for the serious player is the lack of a 'game save' facility, which the Artic program includes. Psion's also lacks the ability to print out a copy of the screen at any time, or a list of moves. Against this, I particularly liked the Psion feature of being able to resign at any time to start a new game. If you get fed up with a game on the Artic program, you have to either continue to the bitter end, or switch off and reload to start a new game. So much for the immediately apparent differences between the two programs. I'll look now at how well they actually play. Both allow castling and enpassant moves, and neither permits illegal moves. I do not play a particularly good chess game, and consequently found both programs hard to beat, even on the lowest levels. Both games seemed to go for check whenever possible, even if they were not in a position to sustain an effective attack. During one game with the Psion program, the program repeatedly went for check from a losing position, and in so doing sacrificed its remaining valuable pieces. This left me with an overwhelming piece advantage, from which I was able to win easily. However, this was a rather unusual finish to a game against the Psion program. In most games I played, the Psion program put up a good, solid defence, and was not easy to beat. In order to obtain a comparison between the two programs, a friend lent me his ZX81, and I played one program against the other. The levels of play of each program are related to the time taken to respond to a move, and are not directly compatible between the two programs. I rang the changes between the three easiest Artic, and the two easiest Psion, levels of play. I must stress that this comparison is a little unfair, as the Psion does not claim to play chess to the standard of the more expensive Artic game. As you may have anticipated, the Artic program played the stronger game. To Psion's credit, three of the ten games were held to a draw. Artic won six, Psion won one. In a game between Psion on the ZX81, playing white, and Sargon II on Tandy, Sargon won, but took some 45 moves to do so. Both played at level one. Both the Psion and the Artic chess programs play a reasonable game. The Artic program plays a stronger, more sophisticated game, and with its save and move listing features will be the more attractive for serious users. For the casual player, who wants just an occasional game of chess, Psion is a reasonable alternative. The Psion program is more user-friendly, and I particularly liked its 'resign' facility. There is little doubt that most ZX81 owners will learn a bit more about their computers, and the game of chess, through playing against any of these programs. On the B side of Psion's chess is CHESS CLOCK. This simulates the clock used in tournaments to limit the amount of time taken for each move. Two digital readouts display the time taken by each player. I thought that CHESS CLOCK was a bit of a gimmick, and unlikely to be used seriously. There might be a few dedicated players who would be prepared to use a ZX81 and a television to time-keep during serious games. I thought the Sinclair advertisement for CHESS CLOCK somewhat misleading. It cannot be used at the same time as the chess program itself as it implied by the statement "... can be used at any time", unless you happen to have two television sets and two ZX81s.

C&VG (Computer & Video Games)

HOW THE KINGS AND PAWN COME TO LIFE Many people have complained about the graphics capability of the ZX81. Now the seemingly impossible has happened. You can play high resolution chess on a Sinclair. ZX Chess needs a few pieces of hardware to produce the graphics but the effect is really startling. The board display shows in clear detail actual chess pieces as they look on a real board and not just capital letter representation. The hi-res graphics version need three pieces of hardware. These are the Ouicksilva motherboard, connector, and character generator. The price of these items is not too high for the effects that you can produce. It is also possible to play ZX Chess 2 without the enhanced graphics. There are seven levels of play. Four of these can be used within competition time limits. You get the option to play black or white using all the legal moves including en passant. ZX Chess needs 16K and is produced by Artic Computing and is available at £12.99.

Sinclair User

CHESS ON SEVERAL LEVELS Available in two versions. The original, with levels 1-6 which uses standard notation for moves, presents illegal move if any other is entered and allows you to play black or white. The full screen is used and the machine code games give a very fast response. ZXchess II has seven levels, one of which, Lightning chess, will respond faster in end moves and opening book moves. The game, however, can recommend your best move and recognise stalemate. Both games will allow you to set up your own board pieces and start from there, thus allowing you to solve newspaper problems without waiting a week for the results. ZXchess II also allows you to copy the board on to a Sinclair printer or to store a game on to cassette. Artic Computing, author of ZXchess, can be reached at [redacted], ZXchess is £8 and ZXchess II £14. All prices in this review have been rounded-up to include VAT and postage where possible.