The chess terms mentioned on the starting page are mostly intuitively used in chess literature. They can lead to misunderstandings and contradictions.

Oops tries to avoid this. He only uses terms, which are well defined and consistent when looking through the magnifying Zermelo-glass, i. e. respecting Oops 8 theses for any position. As every chess player does, Oops looks at positions from both sides of the board, asking: What are the threats of the opponent? How can I refute the threats and - if possible - what threats can I create for the opponent?


Instead of using a lot of words Oops will combine the fundamental outcome of a game

to characterise any chess position by symbols like, e. g. (+/-). A (+/-)-Position is a chess position, which is winning for White, independently of the right to move. The signs (-/+) and (=/=) also represent positions independent from move order. All other combinations represent positions which depend on move order. In such cases Oops uses the square brackets ] and [ showing that this side has just moved. A (+/=]-Position therefore is a position with White to move. White is winning. Black could draw, but - unfortunately - he is not allowed to move.

These symbols require quite a bit of getting used for chess players. But some authors of chess end game books use it the same way (without Oops square brackets). Oops hopes, that after a certain period of familiarisation, everyone will - oops - get it.

Consistent Definitions

Every move (i. e. half-move) is either a winning-, a drawing- or a losing-move. There are no other moves (except in the fantasy of an annotator or storyteller). If there are, besides at least one winning-move, also one drawing-move or one losing-move, than the execution of a non-winning-move, clearly stated, is called an error. The same applies to positions without winning-moves, but with drawing- and losing-moves. There are no other errors (except, Oops has to repeat, in the fantasy of an annotator or storyteller).

An move of the side not to move, or an additional move of the side who has to move, is called, oh dear, nullzug. This kind of forbidden move is not invented by Oops. There are a number of chess apps with a menu item called nullzug. Oops recommends using this item to get familiar with it.

A nullzug, which parries all winning-nullzugs of the opponent, as far as existing, and at the same time is winning, is called, oops, a threat. This term is a little bit shorter than the wording monster nullzug-winning-move.

Oops says, that, besides the essential game idea to free lines, rows, diagonals and squares for pieces and finding paths for promoting pawns to mate the opponents king, recognising, setting and preventing traps is the a and o of chess.

A move is called a trap, if it leaves only one single value preserving move behind for the opponent, such a move must exist, or less precise, if it leads to a position with only a few value preserving moves. If the opponent fails to find this move (or one of the few moves) than he is trapped or lost.

Oops remarks, that threats and traps can be only successful, if the opponent (!) cooperates, i. e. makes an error!

Classification of Positions

Depending on the move order the set of all regular chess position can be divided into 15 different subsets or classes. 9 are named as follows:

  1. Who has to move, wins: (+/+) or nullzug position
  2. White has an advantage, i. e. White wins: (+/=] or nullzug position with advantage for White.
  3. Black has an advantage, i. e. Black wins: [=/+) or nullzug position with advantage for Black.
  4. White is winning: (+/–)
  5. Who has to move, draws: (=/=) or drawn-position
  6. Black is winning: (–/+)
  7. Black is in zugzwang and loses: [=/–) or zugzwang position with one sided zugzwang for Black
  8. White is in zugzwang and loses: (–/=] or zugzwang position with one sided zugzwang for White
  9. Who has to move, loses: (–/–) or Trebuchet-, full-point-, reciprocal or mutual zugzwang position

The last three terms are a little bit cumbersome. Wherever they appear they cause confusion and misinterpretation. In chess books and WWW. It would be better to use the term zugzwang only in connection with (–/–)-positions.

In the following examples Oops uses a special colour code to differentiate between the above mentioned 9 fundamental classes of positions:


Colour code to represent the 9 positions

In those cases, where the right to move is determined by a black or white square on the right side of diagrams, Oops needs only three colours: Green for winning or +, yellow for drawing or =, and red for losing or -.