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Bario. Pieces are undefined until they move. (8x8, Cells: 64) [All Comments] [Add Comment or Rating]
Eric wrote on 2019-05-01 UTC

Panos Louridas, the inventor of this chess variant has a website with explanations and description of Bario: 

Paolo wrote on 2016-03-01 UTC
This looks really an exciting idea. Did you consider to add Fairy pieces to the mix?

Ivan Roth wrote on 2011-03-12 UTC
Hmm.  I think that Bario does screw with piece dynamics, although a queen is still very valuable in the endgame.  Having now had a chance to play this physically, I agree that it is very fun, and that it stretches the mind in ways that normal chess doesn't (In particular, making sure not to trigger a recycle while your opponent has a realized piece that, once virtual, could immediately capture your king).  I'm not sure about barionic, I might try it out if there's a zrf.

By the way, this info page should be updated in light of the comment below which claims to have located the relevant article.

M Winther wrote on 2011-03-11 UTC
An awkward aspect of Bario is that a rook and a bishop becomes much stronger than a queen, due to the movement choice he has when the pieces are in potential state. It wrecks the relation between the pieces. If you play well and gain material, it might turn out that the opponent is stronger anyway. But it could be fun. That's why I said that it was for entertainment, not serious chess.

In Barion Zillions plays much better, that's the point. Probably it lacks those unfair characteristics of Bario. Whether it's a good variant I don't remember. It's from 2006.

Ivan Roth wrote on 2011-03-11 UTC
I don't see what you mean about it not being a serious variant, I find that it has quite complex strategy, perhaps more so than normal chess. As for Barion, I don't see that it is really very different, aside from the added complexity of the quantums getting a one-time teleportation before they stabilize.

M Winther wrote on 2011-03-08 UTC
If it's my implementation you have used, it is very lousy and should be reworked. The code is too heavy and slows the program down. Nor does it follow the initial rules exactly. But I never got around to it because I think the variant is inferior. It is not a serious variant, but merely entertaining. Maybe you could try Barion instead, a related variant, which Zillions plays better.

Ivan Roth wrote on 2011-03-08 UTCExcellent ★★★★★
Now, I have never beaten Zillions at any game before, or even brought it to a draw, on any difficulty setting. In Bario, I bring it to a draw any time, always have the clear advantage in the endgame, and check frequently. This is all on the 'Expert' setting. I think the AI's main problem is that it doesn't understand the value of a queen, which cannot be substituted in capture. It allows its queen to be captured, leaving me with an advantage, since I am more careful. In general, it seems to have difficulty judging the relative value of the pieces. Is this a function of the implementation, or is the game itself too abstract for Zillions? I have yet to play this game against a human, so I may be missing something. Food for thought.

Alfred Pfeiffer wrote on 2006-03-21 UTC
I could contact the inventor Panos Louridas and resolve some of the details
that remained untold in the article and my previous comment (19.01.2006).

First I should mention again, that an essential paramater in this game is
the _number of types_ of pieces that a player owns. If it is only 1 or 
less then for this player virtual play never occurs. This ruling principle
will help (I hope) to understand the following clarifications.

1) We should complete the rules about the capturing of pieces (real
or virtual) by the following:

If the number of types of pieces (real and potential) of a player will 
reduced by the capture to 1 and he owns virtual stones yet then the 
virtual piece(s) of this player will be replaced instantly by the 
potential pieces they stand for, and this event is not the start of 
a recycling (because such players are excluded from playing with 
virtual pieces).

2) Promotions of Pawns:

The owner of the pawn chooses (at usual) a piece to become for the pawn.
This pieces goes to the resevoir and becomes a virtual piece on the board

then and only then if the number of types of pieces in the reservoir 
will be greater than 1 (including the new piece by the promoting).
If this condition is not fulfilled the promoted piece stays a real piece.


a) Before the promoting of a pawn the player does not own any other 
   piece.  Then the promoted piece will remain real evidently.

b) Before the promoting of a pawn the player owns only one type of other
   piece(s) (always real by the rules mentioned above). If he chooses
   for the promoting pawn the same type as he already owns then all
   of his pieces will stay real; if he chooses for the pawn a piece of
   another type then instantly all of his pieces will go to the his 
   reservoir and will be substituted by virtual piecs on the board.
   Furthermore the player also will take part again in the future
   recycling cycles.

c) Before the promoting of a pawn the player owns more than one types
   of pieces, but all of them except one are already in the real state.
   If now the player chooses the same type of piece like the one that
   is represented by his last virtual piece then the promoted piece
   stay real; if he chooses a type other than that of the virtual
   his promoted piece will become virtual and the choosen type of
   piece will be added to his reservoir.

d) Before the promoting of a pawn the player owns more than one types
   of pieces and at least two of its pieces are in the virtual state 
   and stand for different types.  In this case the promoted pieces
   always becomes a virtual piece and the choosen promotion goes to
   the reservoir.

Friendly Greetings,
Alfred Pfeiffer

Adrian Alvarez de la Campa wrote on 2006-02-03 UTC
Interesting...I independently invented a similar game, which evolved into Undecided Chess (the ZRF is here). In my game the pieces start out as berolina pawns, which then can change into other pieces by moving like them. and there is only one 'cycle'. If anyone would like to play it with me over Zillions or by mail, let me know.

Mats W wrote on 2006-02-03 UTC
I have implemented Louridas's 'Bario' for Zillions. It's a sophisticated cyclic chess variant. It doesn't play well, but it's good for studying this interesting chess variant.



Alfred Pfeiffer wrote on 2006-01-19 UTC
Dear chess variant friends,

now I querried in my old magazines and found the relevant text:

Panos Louridas: 'Eine Skala der Intelligenz', ROCHADE 3/1998.

Here I summarize some facts from the article:

Inventor: Panos Louridas (also known as problem composer)

First(?) public presentation: 1985 in the chess club 'Aachener Schachverein 1856'

Rules: The text does not contain a formal listing of rules, but describes the essential ideas with examples.

The pieces in this variant (execpt the King and the Pawns) exist in two states: the 'real' and the 'virtual' state.

The King and the Pawns are real pieces always.

At the start of a game on the board virtual pieces are on the places where in an orthodox game the other real pieces stand. (A common hint is to use checker disks for the virtual pieces)

The potential pieces for the changing of the virtuals are outside of the board in reservoirs for each player.

If a virtual piece moves it becomes a real piece. Each virtual piece can move like each potential piece of its player that is still outside of the board. The player who moves one of his virtual pieces replaces this (while or after the move) by one of the potential pieces (from the outside of the board) that can move in this manner so it becomes a real piece. For example: If he does a diagonal move he may take a Bishop or Queen (assuming both are still available) from the outside to replace the disk (virtual piece) with the choosen piece.

If a real piece on the board will be captured, it is out of the game (means it does not go back to the reservoir outside of the board, also it does not become a potential again).

If a virtual piece will be captured, the owner of the captured virtual stone must assign a potential piece from his reservoir (outside) that then is removed from the game.

So always the number of potential pieces (in the reservoirs) match the number of virtual pieces on the board for each player.

If the last virtual piece of a player disappears (by moving or because captured) then this event ends the actual cycle and a new cycle starts with virtual pieces for both players. This means following: All real pieces on the board (of both players) goes to their reservoirs (outside of ther board) and on the board they will replaced with virtual stones.

But there is a relevant exception: If a player owns only pieces of the same type (only Q, or only R, or only B, or only N) then he will not switch to the virtual state. (The case what will happen if in a such situation one of the player's equal pieces is still in the virtual state remained undiscussed.) Also: cycling take effect only to players with more than one kind of pieces.

Castling: Possible with the usual conditions, here for the Rook this means, that the virtual piece in the corner never moved and a player's Rook is still available in his reservoir outside of the board. Of course when castling this virtual piece then becomes a real Rook.

The article does not contain remarks about promotions.

I propose, if a Pawn promotes it becomes a usual real piece, and this piece should go into the virtualisation also when a new cycle occurs. In this manner also a player who for lack of pieces did no longer take part in the recyclings can get back this special feature of Bario.

I hope I could help,
Alfred Pfeiffer

(zzo38) A. Black wrote on 2005-12-04 UTCExcellent ★★★★★
This is a good game, and I like Bario Shogi better. I invented Bario Shogi, and it works good! Try play it sometimes

Larry Smith wrote on 2005-04-19 UTC
In Reverse Bario, factors similar to the one used to deter Bishops from
occupying the same diagonal pattern could be used to deter a player from
obtaining more than the standard number of particular pieces.  For

If piece to be claimed by the quantum is a Bishop,
     -n if the player has 2 or more Bishops on the field
     +n if the opponent has 2 or more Bishops on the field

If piece to be claimed by the quantum is a Rook,
     -n if the player has 2 or more Rooks on the field
     +n if the opponent has 2 or more Rooks on the field


If piece to be claimed by the quantum is a Queen,
     -n if the player has 1 or more Queens on the field
     +n if the opponent has 1 or more Queens on the field

As long as both players remain below the standard number of pieces, these
values would have no effect on the game.  But when one achieves the
conditions, whether through quantum or Pawn promotion, these values would
aid or deter each players' subsequent quantum claims.

I suggest that this value be 5, this should greatly assist the wanting
player while not overly penalizing the achieving player.  The positions
where a player would be able to obtain more than the standard number of a
particular piece should not be often but this potential will influence the

But this value could be weighted differently for each piece type.  For
example, according to their exchange value, 3 for Bishops and Knights, 5
for Rooks and 9 for Queens.  Adding a level of difficulty for those who
enjoy such. [Hand in the air.]
This could also be applied to Bario with neutral quantum, making it
difficult to re-introduce a promoted piece after a Reset if there is more
than its standard number on the field.  Although a potentially rare

Larry Smith wrote on 2005-04-09 UTC
Yes, the dynamics of Reverse Bario could be quite cruel.  But it could be
said that a player who left a powerful piece in a position of
vulnerability before a Reset deserves to have it taken from them.

One problem with looking at a game merely from its potential and not from
its actual play is that often its negative aspects are over-rated.  A
designer must take into account not only the tactics of the players but
also the overall possible strategy.

With examples, we can point out potential pit-falls but this does not
necessitate that every player will succumb.  Just as the Fool's Mate is a
potential in FIDE Chess.

And the advantage after a Reset would not be the sole propriety of one
player.  Both players will have the potential for this advantage, given
the opportunity.

Question: Would a player holding the last quantum before a Reset play it? 
Or would they allow the last neutral piece to be captured?

This would be considered an area for strategy.  Keeping a quantum in hand
to be able to control the Reset, or holding a neutral piece in reserve. 
Imagine the small battles over the control of the Reset.

Gary Gifford wrote on 2005-04-09 UTC
In a Quantom Variant which allowed a player to obtain 3 or even 4 of the 4
Bishops, Knights, and Rooks, and both of the 2 Queens we would need
markers for the Quantoms (checkers, dimes, pennies, etc. would suffice).
But we would also need 2 chess sets to allow White and Black to get their
third Bishop, third knight, etc.  

A danger in this game [of nuetral Quantoms] is that the
'Player-on-the-move' immediately after the reset has a strong initiative
(in an otherwise equal position) because he can likely 'define and move a
Quantom' to gain control over one or more of the other Quantoms.  And, if
pieces were of nuetral color and he had lost a Queen during the opening
phase, he could now define the Bario (Quantom) as a 'Queen.' (Whereas in
the Deductive/Dedicated Bario variant, a player could not make a Queen this
way, as his lost pieces are off the board and pieces that were just on
board remain reserved for their owners, plus the color-dedicated Barios
remain the property of their owner throughout the game... however, they
can be captured.)

But it is important to note that being the one to initiate a cycle reset
can be extremely hazardous to one's chess health in a 'Neutral Quantom /
Neutral Color Variant.'

Larry Smith wrote on 2005-04-09 UTC
Upon further reflection, it would not be necessary for the chess pieces to
be of neutral color in Reverse Bario.  There need be the rule that only 
the player may move their King, their Pawns and any other piece occupying 
one of their quantum(and, regardless of color, all pieces other than 
Kings and Pawns may be claimed with a quantum under specific conditions).  
It just may be difficult to visualize the state of the field without much 
practice.  But this should not be impossible.  And this would mean that 
players need not obtain any special equipment to play a real-world game.

Or they could simply paint the neutral set themselves with model paint.  I 
suggest bright green, this should make the color of the Checkers(quantum) 
stand out.  Plastic Chess and Checker Sets often can be found for only a 
dollar or two. So that would not be a huge investment in material.

Larry Smith wrote on 2005-04-09 UTC
It is necessary to utilize similar tokens to indicate these neutral quantum
in a real-world game of Bario.  May I suggest red Checkers, they are quite
apparent on the field.  The players then put their pieces on these tokens
as they move them at the turn.  So when a Reset occurs, the players can
quickly remove their pieces but leave the quantum on the field.

Most neutral quantum will be fairly easy to determine which player has
control. There will only be a few instances where 'long' calculation
will be required, and this will often only occur during some of the
mid-game and the end-game.  

Quantum which are equal to 0 would remain un-defined.  Players would have
to perform moves in order to gain control(remember that the proximity of
the King is one of these factors).

The difference in number of pieces that the players have in hand will be a
fairly easily calculated factor.  And any advantage in the exchange will
allow the player opportunity.

Gary's suggested form of play is quite interesting, rather than the
players having potential pieces in hand they could hold owner-specified
quantum(Checkers, red for White and black for Black).  Pawns and Kings are
owner-defined, the remaining pieces in their standard set-up are all of a
neutral color.  Thus players can take control of any of these neutral
pieces, regardless of rank, under specified conditions.  When a Reset
occurs, rather then the pieces, the quantums are returned to their
specific player.  This might be called Reverse Bario.

In Reverse Bario, when a Pawn promotes the player will gain an
owner-specified quantum with the neutral piece.

Gary Gifford wrote on 2005-04-09 UTC
The quantom mathmatical factors would change on every half move and I think
that making the calculations manually might be a bit tedious at times.  To
determine, for example, whether a quantom belonged to white or black, may
detract from the fun of the play. Aside from that, the game should be
enjoyable.  But I imagine in most cases the Bario numeric aspect could be
easily seen to be + or - and so no actual calculation would need to be

A good strategy in this game would be to move (define and identify) the
quantoms that you had marginal control over... thus making them pieces
that your opponent could not control.  Another logical move would be to
capture quantoms whose numeric value favored the opponent.

To make Mr. Smith's proposed game more impressive (perhaps he already has
this in mind) I suggest not using a 'standard' chess set of Black and
White at the start of the game... but rather nuetral pieces (that will/can
become black or white).  This would allow the following, for example: 
Assume an endgame with White having King, 2 Bishops, 2 Knights.  Black
having: King: 1 Knight, 2 Rooks.  Also assume there are 3 unknown quantoms
on the board (ones that in the simple deductive variation would be 2 Black
Bishops and 1 Black Knight) .  With White previously having his Queen and
2 Rooks captured, what could he make of a Bario? [Note: In the
deductive/assigned variant these 3 Barios would already belong to
Black]... Using the nuetral quantom and neutral piece-color concept White
could make a third Knight or third Bishop.  And later a fourth knight or
fourth Bishop.  Thus, we would still be playing with a 32 piece set, but
only the King and Pawn colors would be true White or true Black at the
start of a game.  Of course, the quantoms behind each pawn are so
obviously under each players control there is no danger of the opponent
controlling these during cycle 1.  

It is the first new cycle that the undefined color aspect would really kick
in.  I would not mind playing this tye of game.  But I would not want to do
the math each time.  Of course, for most cases the Bario control would be
obvious and no calculations would be needed except in cases where the
quantom value was near '0.'  When it is at '0' is the Bario up for
grabs or off limits?  I may have missed that answer in an earlier

I think this has the potential to become a great game.

Larry Smith wrote on 2005-04-09 UTC
Another factor which might be used to determine a neutral quantum is the
number of potentials which each player has in hand.  This will allow one
with the larger amount more opportunity to express them.  It can also be a
decisive factor in the end-game when the players might be reduced to Kings
and a single quantum.

This will also have an effect during the mid-game, allowing players to
utilize pieces which might be rather remote from the fray.  Although the
number of quantum may be reduced by capture the number of potentials will
continue to have a factor on the field.


+1 for each potential in hand by player
-1 for each potential in hand by opponent

This will also have an effect during the opening as the players will
express their potential in a rather even fashion, attempting to avoid the
loss of one of their quantum.  A player will be able to express several
potentials before the reduction will be a detriment to the initial set-up.

Larry Smith wrote on 2005-04-08 UTC
Here's a simplified formula for determining use of a neutral quantum.

(The following values are tentative.)

+1 for each friendly piece adjacent
-1 for each enemy piece adjacent
+1 for each friendly piece defending
-1 for each enemy piece attacking.
+1 if on file behind a friendly Pawn
-1 if on file behind an enemy Pawn
+10 if adjacent friendly King
-10 if adjacent enemy King
+5 if friendly King two cells away
-5 if enemy King two cells away.
+1 if friendly King three cells away
-1 if enemy King three cells away.

(The following factors are applicable if players are concerned about
the diagonal pattern of their Bishops and can be weighted accordingly
to deter Bishops occupying the same diagonal pattern.)

+n if piece is to be a Bishop and 
	there is no friendly Bishop on that particular diagonal pattern
-n if piece is to be a Bishop and 
	there is a friendly Bishop on that particular diagonal patteern

There are many other possible factors to consider when evaluating the
potential of a quantum.  All factors should be considered for each


If quantum . . .
	> 0 belongs to player
	< 0 belongs to opponent
	= 0 remains undefined


It may be suggested that whatever values are utilized that they should be
fairly uniform for easy recall, and that the result be a whole number
rather than a possible fraction.

Gary Gifford wrote on 2005-04-08 UTC
Sorry that my last Bario comment was incorrectly interpreted as a distraction by at least one individual. It was not intended as such, but perhaps some people are easily distracted. Should David Short be interested in that 'Existentialist Bario Chess' project I am sure he can accomplish it fine on his own. And I would be glad to assist him, but only if requested to do so. In regard to other Bario projects, best regards to all involved with them. Meanwhile, the variation CarlosCarlos and I are playing is working fine and seems quite intersting, while not being difficult to understand.

Larry Smith wrote on 2005-04-08 UTC
I think that I will concentrate on Bario for now.  Thanks for the attempt
at distraction.

With your statement that a neutral game would result in a possible large
number of quantum located around the King.  It would be necessary that the
King is a weighted factor in the determination of which quantum will be
utilize by the player.  Thus the closer your King to a quantum, there is
an exponential factor that you will increase the opportunity to take
possession of such.

The proximity of Pawns could also play a part in determining the
possession of a quantum.  A simple rule might be to state that a quantum
located on a file behind a player's Pawn(regardless of distance) would
have an added factor.  This would increase the opportunity to gain
possession of quantum on the player's side of the field.

As pieces are delevoped, their proximity to quantum will also have an

Gary Gifford wrote on 2005-04-07 UTC
In the penswift/CarlosCarlos game a 'full-field reset' has taken place. 
We are using Player-defined Barios.  If we were using nuetral Barios, such
that they were up for grabs by the player on the move, then I would have
had to avoid the reset as my King would be under heavy Bario attack.  This
is not a criticism of the nuetral Bario concept... it is only a note that
may help Mr. Smith in figuring out his rules for nuetral Bario use.  At
this point in time I remain in favour of Barios that belong to the

However, in regard to Mr. Smith's desire to create a very complicated
game, I would suggest the idea of getting together with David Short, the
creater of Existentialist Chess and creating a Bario version of that game
(if David Short was open to the idea.)  If Mr. Smith (like the creator of
Bario) is hoping for the creation of a complex game, then I think that a
Bario Existentialist Chess (or a Existentialist Bario Chess) would be hard
to top for complexity.  But, again, if that were to be attempted I think
that David Short should be contacted.  I believe that Existentialist Bario
Chess would be a most complex game, much more so than we are likely to get
from Bario which begins with a standard chess set, and is really a variant
of Fischer Random Chess with hidden pieces and resettable pieces.  Of
course, those factors do make for a tremendous difference in the 2 games.

Larry Smith wrote on 2005-04-07 UTC
The original graphics for this page showed all the quantum as similar. 
They have since been changed to differentiate them. At this point it appears to be a matter
of preference.

The difference between a Field and Player Reset: In a Field Reset all the
quantum on the field must be defined.   In a Player Reset, once one player
has defined all their potential quantum(there may still be other un-defined
quantum on the field).

I actually opt for the Field Reset.  It seems to comply with the stated
rules.  The same with the Actual determination of the quantum.  Thus my
preferred condition would be Full Field Actual Reset.

I would also opt for the quantum as neutral.  This would greatly increase
the level of difficulty in the play.  All that needs to be determined is
some form of conditionals by which a player may take possession of a
particular quantum.  

I have been working on a very intricate formula, involving not only the
adjacent pieces to the quantum but also including the conditions of cells
beyond.  Granted that this form of play may not appeal to most, but I
always look for ways to increase the difficulty in quantify a game rather
than making it easier.

And the author of this page states that the inventor intended for this
game to be the most difficult on Earth. ;-)

Jared McComb wrote on 2005-04-07 UTC
I am going to offer my interpretation/variant of the rules here.  This is
assuming each player has their own distinct set of quantae, which is how
it looks the game is played from the opening setup on this page.

A piece is not defined until it is moved, regardless of whether it can be
deduced as something or not.  In other words, the cycle is not complete
until every quantum on the board has moved and been defined.  When you
move a piece as a rook or bishop, you may choose to define it as a queen,
but you must define it as such immediately after moving it.  Once a piece
of yours has been captured, it's captured, and you can no longer define a
quantum to be that particular piece (of course, if you had two of them, and
one was captured, you can still use the other one).  If a quantum is
captured, we don't know what it was going to be, so after every piece of
yours has been defined, all the other ones that are still left are
considered captured and given to your opponent.  Of course, immediately
after the last quantum has moved, the cycle ends and each quantum suddenly
has the moving power of all the pieces you have left.

In other words, I'm for Full Actual resets, but I don't understand fully
the difference between Field and Player, so I can't say which I have just
stated I prefer.

The reason I like this method of play is that it more closely resembles
FIDE chess because once a piece is captured, it's removed from play, so
for example you can't redefine another quantum to be your Queen if
you've already lost your Queen.

Just my 2 cents.

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