Let's invent some very weird pieces

One more puzzle dedicated to the builder:

All friendly pieces adjacent to the same friendly builder inherit each other's movement/capture capabilities (without special functions like royalty). From the position below, both the bishop and king temporarily act as bishop-king compound.

I also decided that the builder can only move 1 single step orthogonally, and cannot capture himself.

This gives crazy openings. But now for an endgame. I'm still figuring out if this would be a forced mate:

It's hard to believe white can get a forced mate from that. As soon as a piece moves away from the builder, he becomes his normal piece again, so white has not much more than a bishop and a king. I would think a builder is most powerful in middle game, and two pieces are next to him with non-redundant moves. Like a rook and bishop next to a builder would make two queens!

But let us know if you find a force mate sequence 

As for my "town idiot" piece - he's "on-hold" until I can find some better rules for him. I put him in a game for a short while, and he didn't do much to make anything more interesting. So now I have these extra little icons, but no move for him yet.

Maybe there's something else to do with them? He was designed to look unimportant and he wears the crown of the wrong army, so he might be a fool? And maybe a piece that is somehow in play but belongs to neither side? If anyone has any good ideas let me know!

Just out of curiosity, Vickalan, how exactly do you produce the quite colorful symbsol for these chess pieces? For example, the 'town idiot' from your previous post. ^^

I may need such a program. haha

Also,

vickalan wrote:

 

 

It wears a crown just because it's not too smart - but isn't really royal in any way. 

 

Instead of crown-shaped, why not make it triangular-shaped, in order for it to be a dunce hat? =D

My first impression was that forcing mate should be very easy, with Builder + Bishop. On a 10x8 board. Of course groups of short-range pieces eventually always lose their mating potential when the board gets large enough. But it is usually the smallest dimension of the board that determines this, and 8 is pretty small. (A Kig, Builder and Bishop in a row already cover a 3x5 area.) And B is not really short-range; there is a conjecture that Bishop would be able to force mate against a bare King incombination with any piece that can attack squares on the entire board. (That does not apply to a Builder, however.)

The point is that K+B can keep the bare King confined to a triangle around a certain corner, the winning King guarding the squares on which the bare King could step to cross the Bishop diagonal by taking opposition. The bare King can only threaten to cross the diagonal by keeping moving in the same direction along that diagonal. But it cannot do that forever, as eventually it will encounter the board edge. And whenever it flips direction there is no immediate threat of escape, so the winning side has a 'free move' with his third piece, which he can use to position it in a way that allows you to move up the Bishop, to shrink the triangle.

Mate in the corner of the color of the Bishop (say a1) is always possible, with a third piece that can attack b1, as the Bishop can switch its attack from c1 to a1 in a single move (and triangulate, to make sure you attack b1 when the bare King stands there).

I just use "MS Paint". I think it's preload on most PCs with Windows 10.

I can add a dunce hat to my last piece, but first I need to decide how he moves. I'm trying to think of something like a pawn, but even simpler or something weird (and it has to be interesting in game-play)

Well, it is as I thought. I modified Fairy-Max to play with a Builder in this end-game (using the simplified rule that all pieces move as a B+K compound whenever there are two black pieces next to the builder of the side to move), and started it from the position

8/8/8/8/3K4/8/8/u2k1b2 w - - 0 1

(so I used an 8x8 board; U =Builder). I gave the losing side 10 times more time than the winning side (40moves/10 min vs 40 moves/min). Black needed 28 moves to checkmate the bare King:

[Event "Computer Chess Game"]
[Site "ONTWIKKELLAPTOP"]
[Date "2017.01.12"]
[Round "-"]
[White "Fairy-Max 5.0b3"]
[Black "Fairy-Max 5.0b3"]
[Result "0-1"]
[TimeControl "40/600"]
[Variant "builder"]
[VariantMen "B:BtW;U:mW;Q:BW;k:tBK"]
[FEN "8/8/8/8/3K4/8/8/u2k1b2 w - - 0 1"]
[SetUp "1"]

{--------------
. . . . . . . .
. . . . . . . .
. . . . . . . .
. . . . . . . .
. . . K . . . .
. . . . . . . .
. . . . . . . .
u . . k . b . .
white to play
--------------}
1. Kc3 {-6.00/17} Ub1 {+5.87/15 2.1} 2. Kb4 {-5.81/17 20} Kd2
{+5.92/13 1.7} 3. Kc5 {-5.72/17 35} Ub2 {+5.92/13 2.2} 4. Kd4 {-5.78/17 28}
Bd3 {+5.82/14 3} 5. Ke5 {-5.74/16 26} Ke3 {+5.74/12 2.0} 6. Kd6
{-5.80/16 17} Ke4 {+5.71/13 2.1} 7. Ke6 {-5.76/17 24} Uc2 {+5.72/12 1.5} 8.
Kf6 {-5.74/16 17} Uc3 {+5.70/12 2.3} 9. Kg5 {-5.72/16 36} Ke5
{+5.67/12 2.1} 10. Kg4 {-5.72/15 14} Uc4 {+5.68/12 2.2} 11. Kg3
{-5.79/15 17} Ud4 {+5.70/12 2.4} 12. Kg4 {-5.72/15 20} Bb1 {+5.82/11 1.3}
13. Kg5 {-5.94/16 18} Bf5 {+5.91/12 1.5} 14. Kh5 {-5.80/16 18} Ue4
{+5.72/12 1.8} 15. Kh4 {-5.69/16 18} Kf4 {+5.60/11 1.2} 16. Kh5
{-5.75/16 17} Ue5 {+5.77/12 2.4} 17. Kh4 {-1000.20/16 14} Bd3
{+5.77/12 2.3} 18. Kh5 {-1000.10/17 29} Be4 {+5.78/12 1.8} 19. Kh4
{-1000.09/16 10} Bf3 {+5.79/11 1.1} 20. Kh3 {-1000.09/17 26} Uf5
{+5.87/12 1.4} 21. Kh2 {-1000.07/18 11} Kg4 {+1000.08/12 2.0} 22. Kg1
{-1000.07/21 11} Kg3 {+1000.07/13 1.0} 23. Kf1 {-1000.06/28 6} Uf4
{+1000.06/16 1.4} 24. Kg1 {-1000.05/28 0.4} Be2 {+1000.05/19 0.9} 25. Kh1
{-1000.04/28 0.1} Bd3 {+1000.04/28 0.3} 26. Kg1 {-1000.03/28 0.1} Uf3
{+1000.03/28 0.1} 27. Kh1 {-1000.02/28 0.1} Bf1 {+1000.02/28 0.1} 28. Kg1
{-1000.01/28 0.1} Bg2 {+1000.01/28 0.1}
{Black mates} 0-1

vickalan, he changed the colors, that's all. And who's move it is doesn't make a difference, it's about finding a strategy to force the lone enemy king to the side or corner, step by step.

Fairy-Max is publicly available, and usually distributed with the WinBoard GUI (e.g. http://hgm.nubati.net/WinBoard-AA.zip ) Whether it is easy to use depends on what you want to use it for. Playing one of the pre-configured variants through WinBoard is trivial. Defining your own chess variants is a bit cumbersome; the format of the game defenitions in the (self-documenting) fmax.ini file is not very user friendly. Engines like Sjaak II are much easier to use in this respect.

Neither Fairy-Max nor Sjaak II offer the possibility to configure pieces with side effects (such as the Builder, magnetic or catapult pieces, immobilizers or activators), though. So I really had to modify the program and recompile it to do the above game with the Builder. For which you have to be a programmer, and understand pretty well how the program works. (The source code of Fairy-Max is also publicly available.)

I took a few short-cuts in this, not writing code to implement a full Builder as described by EvertVB, but a piece with simpler rules that in the K-KBU end-game would behave the same as a Builder, but in other positions could be totally different. (Defining the effect on all pieces rather than just adjacent, always upgrading them to B+K rather than to what was adjacent, and doing this whenever more than 1 black piece stand next to the pseudo-Builder.) And I used an 8x8 board, because that makes it easier to test whether a square adjacent to Builder is on the board or over the edge. All this could be improved by more programming, but as I was only interested in this one problem, and it was already late in the evening, I took the quick and dirty solution.

Allowing 10x8 boards would be comparatively easy. But, like I said, it is usually the narrowest dimension of the board that determines if you can force the mate. As, after you have been forcing your own pieces in the center, you will be driving the bare King towards one of the short edges, and how many extra space there is 'behind' you does not matter. If the bare King could manage to escape by sneaking past your pieces that are supposed to press him to the edge, it just means you cannot do it at all.

If you really want to know which fraction of the positions is won, using an engine is a very inefficient method ayway. Because then you would have to try each position separately. And no matter how much time you allow the defending side, there never is a guarantee that he played perfectly. It would be much better to build a tablebase, which calculates the won positions in bulk. There will always be some drawn positions, however, where the strong side, even if he has the moves, will lose one of his pieces. E.g. where the bare King forks the Bishop and Builder, and the strong King cannot protect them. Or where the bare King diagonally attacks an uprotected Builder, and can chase it into a deserted corner, while the Bishop is blocked by its own King and cannot come to the rescue.

Oh, I didn't study this position a lot yet. In some endgames the color to move makes a difference. At first glance it looks like the black king can't be forced around much, but with careful study he might be in trouble!

OK a suggestion for the town idiot:

It steps 1 square othogonally. It starts on a5 and after each white's AND black's move it 'automatically' steps, while following the trajectory a5-j5 j4-a4 a5-j5 and so on.

It cannot be captured, any piece that is overrun is removed from the board.

===========================

Alternative suggestion:

Both white and black can move with the town idiot (1 square othogonally) instead of an own piece, and it will count as a move. The town idiot cannot be captured but it can capture any other piece. It is illegal for each player to move twice subsequently with the town idiot. If one player directly responds with a town idiot move after a town idiot move, it is illegal to move it to the square where it came from.

Example: white could move Tid. a5-a4. Then Tid. a4-a5 would be (temporarily) illegal for black. Whatever black plays, white must wait one turn before moving the town idiot.

OK, that's a good idea! (I like the first idea more). That could really change the dynamics of a game because pieces will have to "clear out" as the town idiot moves around in his rectangular pattern. But he doesn't move too fast so both sides have fair warning. Let's play a game like that!

Btw, in case the name idiot is too strong, other names might be: fool, moron, ox, or cretin. Let's get image, details, (and name?) figured out soon and we can start.

Here's another weird piece, this one for entirely different reasons:

I would like to announce several pieces of very unusual movement or mechanics.

Shadow or shoggoth:

The idea is a colorbound universal leaper, ie, an universal leaper (a piece that can move to any square) but limited to only one colour.

Trickster: 

I thought in a piece that moves like a queen, but once moved like queen, it will be put down and only can move like knight in its next use.

And when moved like knight, it only can move like queen its next use. 

This will change of movement type each time the piece is used, I think the idea is easy to catch without images.

Phalange pawns:

This is the result of the idea of composed pieces. Phalange individual pawns, with a movement similar to wazir and capture like ferz (move one square in any ortogonal but only can capture one square in any diagonal), can be put in rows of three unities for create "phalange formations" with an special movement. 

This mean, for example, you will move three phalange pawns at the same time, and you can capture until three pieces at the same time with such movement if conditions are appropiate, if these three phalange pawns are placed in alignated row.

The phalange formation of three pieces would be only able to move backward and forward, but any number of squares.

Block:

Inspired by the mayan chess variant.

Block is actually an squared prism with a size of 1x1x2 board squares.

Block will move rotating on its edges over the board, ie, this piece moves by lie down, raise and roll over the board.

Due to this property, block has a variable size of one to two squares.

In a common chess variant, block only can effectuate one movement by turn; but in oriental variants (for example shögi) it could be different.

Valkyrie and beserker:

The idea of valkyrie is the idea of a kind of pawn able to do multiple captures (until two or three) in the same turn. Valkyrie should have a bigger capture range than common pawn, with the function of do this minimally more significant in the game than common pawns.

Berserker would be a piece able to do two king movements (and therefore, until two captures) in the same turn. It is inspired in the oriental piece "lion", except that berserker is unable to leap pieces and doesn't need do a first capture for capture a piece in the second movement.

Hangman, harvester or demon:

Hangman is an universal leaper (a piece able to leap to any square of the board). However, hangman only can move for capture. If it doesn't capture, it doesn't moves.

... ... ... ... ... ... ... 

...

Ninja:
Colorbound omnidirectional pawn (ferz) that must move one square in ortogonal (wazir) for capture.
It has the special property of that only can be captured by adjacent or leaper pieces. So, if for example, a rook is in a ortogonal attack position to this, only will be able to capture to ninja if it is adjacent. If rook is further (one square or more), it won't be able to capture to ninja

Another special property is that ninja is transparent to allied and opponent rider pieces, your bishop or an oponent bishop can go through the square occupied by your ninja.

XY positioners (and Z if 3D):

Inspired in the coordinator of ultima chess.

XYZ positiones are special pieces.

These pieces move like queens, but can't capture like queens.

These pieces must capture by coordination, ie:

If X positioner is in a "(x,p)" square, and Y positioner is in a "(s,y)" square, any opponent piece that is in the (x,y) square will be captured.

If X positioner is in 5a (ie, (5,1) and Y positioner is in 6d (d represent the coordinate (6,4)), so any opponent piece in the 5d square ((5,4)) will be captured.

The Z positioner is the same type of piece, but is an addition needed for 3D chess with positioner pieces.

Z positioner represent the (0,0,z) in coordinated attacks.

Very nice. With one block occupying a1+a2 and another block of the same colour occupying b1+b2, who will tell if it wasn't a block occupying a1+b1 and another block occupying a2+b2?