NERO 4 FAQ 03.11.1998 
---------------------

Nero 4 is a long time programming project started by me 23rd August 1998.
Name comes from finnish language. Nero means "genius". As a bonus(?) the
name also means an infamous roman emperor. (And "black" in italish...)
My first chess playing program I made in 1995. I think it was September.

This is a hobby. They don't pay me for writing chess programs. I use my 
freetime to do it. I have used Borland's Turbo Pascal 7.0, writing so far
120.000 bytes of code, which includes everything: program interface, search
engine unit, book unit, and an unit to draw chess pieces. (Book and piece
units are the same than those used by my previous program Nero 3.) 
Perhaps I'll give these sources also for you with the program someday.

Nero is a DOS program. I think he works fastest in DOS mode without 
any Windows stuff running. ('Command prompt only' mode with Win95.)

Nero works on any PC supporting DOS and EGA/VGA. (Should work...)

PROGRAM IS FREEWARE! Give him to your friends too! (However it would
be most encouraging for me to get sometimes thanks in small bills too.)

So far Nero understands only commands given from keyboard, not yet mouse.



MOVING YOUR PIECES:
-------------------

The easiest way is to use CURSOR KEYS and ENTER for moving. Place the
cursor on the piece you want to move and PRESS ENTER. Then place the
cursor on the square where you want to move that piece to, and press ENTER
again. Move is then made. After Nero has made his move, it's your turn 
again, which is indicated by the text "YOUR MOVE" in a small window.


If you happen to own Auto232 using chess board, it's even easier...
Give Nero the command "A232" and play.


Moves can also be given in the form "e2e4", "g8f6", ...
                                     ----    ----


NERO'S COMMANDS:
----------------

You can give commands (or make a move) when seeing the text "YOUR MOVE".
                                                             ---------

List of the commands available can be seen by pressing ESC. 

(If Nero reads capital letters A,B,C,... they are changed to small 
 letters a,b,c,... inside the program. So you can use both styles freely.)

"GAME" or "AN" starts a new game,
 ----      --

"EXIT" or "EN" quits the program,
 ----      --

"MOVE" or "SP" makes Nero move next (i.e. switches sides),
 ----      --

Nero doesn't have Auto232's commands "ZU" (take back move) and 
"DR" (Printer on). In Auto232 mode printer is always on, and Nero
doesn't allow taking moves back. (It is strictly forbidden in real
chess.)


"AUTO" makes Nero continue current game playing against himself. 
 ----
(This can be interrupted by pressing any key on keyboard. But Nero 
first finishes the move he is currently thinking.) When game ends,
he automatically starts to play next game, and next, and next...
until you interrupt him by pressing some key.


"A232" switches Auto232 mode OFF and ON.
 ----

"BEEP" switches sounds OFF and ON.
 ----

"BOOK" switches using of Nero's opening book OFF and ON.
 ----

"VARY" switches betveen normal and varying playing styles.
 ----
When varying is OFF Nero makes the move for which he calculated the
best score. When it's ON Nero picks by change one of those moves with
good enough scores, which means scores of those moves are at least 
the best score minus 0.15 pawns. So Nero can play sometimes different move
than his search information shows when varying is used.


"RAND" switches random playing OFF and ON. 
 ----
When random playing is ON Nero just makes by change one of the legal 
moves. So this should be very easy for you to win...


"MODE" Switches 2 players mode OFF and ON.
 ----
 You can e.g. play with your friend and let Nero check that your moves
 are legal. (And your moves can be saved then too.) Or use this to give
 initial moves (e.g. your favourite opening) in the beginning of a game
 against Nero.


"+" and "-" ( and '*' and '/' )  change the level of thinking.
 --------- 
'+' adds five seconds to Nero's thinking time, '-' subtracts 5 seconds 
from it. The fastest level is 0 second per move, the slowest 72000 s = 20 h.
If you want to add/subtract a lot of time, hold the '+' or '-' key down
for a while. Or add 100 seconds with '*' and subtract 100 with '/'.
When level is less than 15 seconds/move only one second is 
added/subtracted when '+' or '-' pressed.



FILE FOR SAVING PLAYED GAMES:
-----------------------------

Played games can be saved to a text file. They are in an easily readable
form. (They can also be readen and replayed by popular PGN reading
program CHESSBD by Don Fong. Perhaps with some other programs too, but I
have not tested that.) If you want the games (ALL) to be saved, give
filename when asked in the beginning. If you don't give filename NOTHING
will be saved.



SHOWN SEARCH INFORMATION:
-------------------------

You can see blue texts in three small windows while Nero is calculating.
First Nero searches for possible forced mates up to mate in 30. This is
shown by "#?#?#?#?..." string. (He doesn't find mate, if it's not "forced 
enough" i.e. opponent having very few replies to each move in mating line.
May still find mate while searching "ordinary" moves of course.) For mate
searching Nero uses max 30% of his thinking time. (In a few cases mate
searching can take a little longer, but not often. In most positions mate 
searching is interrupted very soon, forcing enough moves are found seldom.)

(If you tell in setup, that you gave a mating problem, Nero will find a mate 
 in the asked number of moves. If the problem has many solutions you don't 
 get all of them. Nero makes just the one mate he can find first.)

Then Nero starts searching for other moves. In bigger window he shows 
best move found in previous searching depth. Nero's score is -100 if he is 
one pawn down, and so on.

Finally he shows the depth of the search as two numbers, first one 
telling the depth for all lines, and the other announcing the depth 
of the deepest searched lines. E.g. 'depth = 6/8 means that for six
halfmoves all moves were taken into account but deeper searches 
plies 7-8 were made selectively.

In a smaller window Nero shows the move he's currently evaluating, and
an ordinal number, which means moves rank, when legal moves were sorted
by score according to previous searching depth. And after a '/' the 
number of all legal moves in current position. (Except under-promotions
are not there yet.) The number of evaluated positions can be seen in the 
window in lower right corner of the screen.

If Nero can make a book move, or there is only one legal move for him,
or you have chosen random playing mode, he moves at once without showing 
search information. (Because there is nothing to calculate.) 



INTERRUPTING NERO'S SEARCH:
---------------------------

If Nero is playing against himself (command "AUTO" starts this) you can
interrupt it by pressing any key. You can also interrupt him, if he
thinks too long for a move, by pressing some key. But interrupt doesn't 
work until at least 30 seconds of time is used. (After 30 seconds of 
evaluating he starts to check if some key has been pressed.) This is
because you could press some key by accident... If you are loosing a
game and don't like it ... I recommend to give the command "rand" for
a couple of moves... (Of course I have never done that myself... ;-)



SETUP AND SOLVING FOR MATES:
----------------------------

You are asked, when starting a new game, whether you want to play a game
(started from ordinary starting position) or setup the position. If you
choose setup, you can give every kind of positions e.g. mating problems.

Cursor is first on square a8. If you want e.g. to have a black queen there,
you should press 'q'. (For empty square press e.g. space.) Cursor moves
to b8. You place the piece you wish to have there. And so on. If you
press a wrong button, you can't take it back, but fill the rest squares
with something, choose again 'New Game' and start again from the beginning.
(I'll make takeback feature there someday.)

After placing piece to last square (h1), Nero asks you which side is to
move next. Take care that you answer correctly to this.

If your position is a mating problem, give Nero the number of moves
following the instructions he gives you.

If the position you gave is a mating problem, and you want Nero to solve 
it, give him command 'MOVE' after setup. With command 'AUTO' Nero will 
start a new game after checkmate, and perhaps you have then not enough 
time to see what happened... So it's better to use 'MOVE'-command here. 



OPENING BOOK and THANKS!:
-------------------------

OPENING BOOK includes over 300 opening lines. Nero chooses randomly
which line to play. Longest lines are 13 moves for each side. There are
also some trap lines. I THANK my friend Frank Bos who has helped me a lot 
to improve the book! He has also given many other valuable suggestions!

There are many others also who I must thank: Ralph, Harri, Karsten, Jarmo, 
Hans, Giancarlo... and many who post their articles to Computer Chess Club
and rec.games.chess.computer. Many have given encouragement and help to me.



FEATURES SOME DAY IN THE FUTURE:
--------------------------------

- Giving moves and using menus with mouse.

- Blitz levels  M minutes per game (where M is user defined).

- Turning the board. (Now white is always at the bottom of screen.)

- More lines in opening book. (Send your recommendations! If possible in
  a format like "e2e4e7e5g1f3b8c6f1b5...")

- Promotions also to rooks, bishops and knights. (Now only to queens.)

- Principal Variation, killers... (Which Nero doesn't have yet.)

- Hash & other kind of tables... (Not yet used either...) 

- Your ideas are very welcome!



LAST CHANGES:
-------------

- Some changes and fine tunings in search. 


        Best Wishes,
                                        Jari
