About Chad
Chad is the result of an exercise in mimimalism. The question that triggered it was:

"How much is actually needed to make a chess variant?"

Obviously it requires a king. Obviously 'pieces' wouldn't be considered an excessive feature either, but pawns? Why pawns. No pawns.

And different pieces? There's the king of course, but why different pieces. No different pieces. Nor mutual capture of pieces for that matter. Chess is about capturing the king, not slaughtering an army. So I gave the king the traditional move, provisionally, and chose rooks as the most logical pieces on a square board.
Now what?

It was soon established that a king in the corner with two orthogonally adjacent rooks constituted an impenetrable fortress, which left nothing else for the remaining rooks to do than strolling about aimlessly and having tea. It eventually became clear that without mutual capture of pieces, the game wasn't going anywhere. But having rooks slaughter one another all over the place, with mutual impotence as the most likely outcome, wasn't too tempting either.

The Wall
The solution that eventually emerged was the 'Wall', the twelve squares you can see around each castle in the diagram. It serves to restrict mutual capture of pieces to one specific condition: the mutual right to capture exists only between an attacker on the wall and a defender inside the castle. That in turn begged for promotion of an attacker that actually managed to enter the castle, and that in turn begged for a more flexible king, leading to the additional knights move.

Chad became very popular at the games club Fanaat of the University of Twente, with two top players demonstrating convincingly that it showed no lack of finesse.
As an exercise in minimalism it was ironically overtaken by Shakti, a chess variant that unintentionally happened some time later. It doesn't make Chad any less of a great game.

Initial position Rules
The diagram shows the Chad board with the pieces in the initial position. The areas covered by the pieces are called the castles Each castle has twelve adjacent squares that together constitute the wall.

  • White begins. Players move, and must move, in turn.
  • The king is confined to his 3x3 castle. He may go and capture using either the king's move or the knight's move.

It's customary to look at the king in terms of the squares it does not cover. In the center it covers the whole castle, on the side it does not cover the square on the opposite side, and in the corner it does not cover the other corner squares.

  • The rook moves like the rook in Chess, unhindered by castles and walls. If it ends its move inside the opponent's castle, it is promoted to queen.
    The queen moves as the queen in Chess, unhindered by castles and walls

  • A king facing an opponent's rook along a rank or file is in check. A king facing an opponent's queen along a rank, file or diagonal is in check.

  • Barring one particular situation, pieces other than the king cannot capture one another and thus only block one another. The mutual right of capture between pieces other than the king exists, and only exists, between an attacking piece that is on the opponent's wall, and a defender inside its own castle.

This is a crucial rule! It is illustrated in the next diagram. Black's castle shows a rook on the wall facing a defender inside. In such a situation both have the right to capture. However, in this specific situation only white can capture because the black rook is pinned! This position shows one of the basics of attack.

Either to move and win If it were white's turn he could checkmate in two and if it were black's turn he also could checkmate in two.

So let's also disregard the pieces around White's castle for a moment and consider the postion around black's castle. What can black do?

Interposing a piece on any of the squares between the black rook and either of the white rooks, would parry the immediate threat. If this isn't possible, black's only option is to move the defending rook towards the pinning one. But this leaves a white rook on the wall attacking three squares inside the castle - literally a thorn in Black's side.

Needless to say that the white rooks illustrate a basic attacking pattern. It appears in a variety of forms in almost all attacking concepts.

But as mentioned, if it were Black's turn in this position, then he could actually checkmate in two:
  1. 1. … ED2
  2. 2. D4C5 (or D4E5) D26++

A related basic concept is the promotion sacrifice. It derives from the fact that an attacker, once it is inside the castle (and thus automatically a queen), can only be captured by the king.
A king on the side leaves one square unprotected, and a king in the corner three. The sacrifice of a piece to force the king to the side or into the corner, to clear the way for a second piece to promote on an unprotected square, is very common.
A queen is worth the sacrifice of a piece anytime! Its strength is illustrated in the same diagram: if it were black's move, the lone queen could checkmate the white king in just two moves.

In positional respect, a rook on a square diagonally adjacent to the enemy castle covers two segments of the wall. Needless to say these spots are popular. Finally, every attack eventually draws from defending forces, so an attack to checkmate should drive home. If it fails, 3-fold is one's only hope!

An example game
no Sound  -  Flip board
Broken canvas...
to move

Ed van Zon-Christian Freeling (1-0)

Chad © MindSports