Fischer random chess numbering scheme: Difference between revisions

Revision as of 01:34, 22 March 2022

Revision as of 01:59, 22 March 2022

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Both methods take account of the positions of the bishops first, and ignore the distinction between the king and rooks. Once the positions of the bishops, knights and queen are known, there is only one possibility for the remaining three squares. In the places where division of whole numbers is done, it is always done giving a quotient (designated q1,q2,..) and a remainder (designated r1,r2 ..).

There are 16 ways to put two bishops on opposite colored squares. These are shown and numbered in the small table belowabove. The entries actually can be calculated using simple arithmetic, but the table method seems less error prone. For the standard SP the bishop's code is 6.

'''Scharnagl's Bishop's Table'''

{|class=wikitable

|-

| 0 || BB------ || 4 || -BB----- || 8 || -B--B--- || 12 || -B----B-

|-

| 1 || B--B---- || 5 || --BB---- || 9 || ---BB--- || 13 || ---B--B-

|-

| 2 || B----B-- || 6 || --B--B-- || 10 || ----BB-- || 14 || -----BB-

|-

| 3 || B------B || 7 || --B----B || 11 || ----B--B || 15 || ------BB

|}

In any SP, when looking at the arrangement of the other pieces around the bishops, it is helpful to write down the NQ-skeleton for that SP. This is done by ignoring the bishops and replacing the "K" and "R" by a common symbol, say "-". The NQ-skeleton for the standard SP is -NQ-N-. The sections below showing Scharnagl's Methods and the Fritz9 Methods are independent, and may be read in any order.