20 March 2012

Chess Informant Endgames

In Four Endgames to Know, where I built a database of endgame positions from a number of books on the subject, there was one important resource missing : Chess Informant (CI). Through the years, the company has released a number of useful endgame products, encompassing both hardcopy and digital formats.

The most comprehensive CI endgame product is the 'Encyclopaedia [Encyclopedia] of Chess Endings', published in the 1980s in five volumes:-

  • Vol.1 - Pawn Endings
  • Vol.2 - Rook Endings 1
  • Vol.3 - Rook Endings 2
  • Vol.4 - Queen Endings
  • Vol.5 - Minor Piece Endings- Knight & Bishop

The CI endgame classification scheme has always been a mystery to me, so I was glad to find an explanation at EG online (EG90).

No. 90 - (Vol. VI) • NOVEMBER 1987 • THE "ECE" ENDINGS CLASSIFICATION SYSTEM • by Paul Lamford, London

"ECE" is the ENCYCLOPEDIA OF CHESS ENDINGS. The classification system of the twice-yearly Yugoslav CHESS INFORMANT ("CI") will be known to active chessplayers: each opening is given a code from A00 to E99, with transpositions cross-referenced.

In 1982 CI published the first volume of five that will systematically cover all endgames. The series draws on the data base built up since 1966. In addition many other endgame books, including 'Averbakh', have been keyed in. (What about copyright? A JR.) When complete the whole will represent the most comprehensive reference work available. Of the five volumes, PAWN ENDINGS and ROOK ENDINGS I and II have been published, with MINOR PIECE ENDINGS and QUEEN ENDINGS expected over the next few years.

The first principle of the classification system adopted is the "most valuable" piece on the board. Thus R + P vs. S will be found in ROOK ENDINGS; Q vs. R + B + S will be in QUEEN ENDINGS. Within each volume will be found up to 100 subclassifications, for example Q00 to Q99 (ECE actually employs figurines, not Q, R, B, S, P). It is at this point that there is a radical departure from GBR principles. With the ECE code it is not possible to determine the sub-classification without referring to a detailed index and this varies with each piece-ending.

The full index runs to 53 pages and was published in 1978 as part of the CI anthology THE BEST ENDINGS OF CAPABLANCA AND FISCHER, a pilot run for the five-volume series.

Certain general observations about the second level classifications are possible. The first breakdown of each volume is into ten sections, generally by material, ignoring PP. For example, RO comprises (all) R vs. PP and R vs. bare K, while R8 comprises (all) double-R endings, with R9 containing endings with more than 4 pieces. This covers the first "decimal place" of the hundred sub-classifications.

The second decimal place is generally by the number or disparity of PP. For example R3n (single -R endings) starts with R30 which includes R vs. R endings (without PP) and R + P (one P only) vs. R, while R38 is all single-R endings with 2 extra Pp. In all volumes the final classification (n9) includes all material not in the previous 0-8.

The 'data base built up since 1966' undoubtedly refers in part to the endgame section of CI's flagship product, the 'Informant' itself. The company sells a digital version of those endgames: Chess Informant 5-99 Endings Section. I located a copy, loaded it into my own database, and ran a few queries. The first result that popped out was a count of the types of endgames in CI 5-99, using the ECE classification scheme. The 2494 endgames are distributed as shown in the following table.

EG Tot 0 1 2 3 4 5 6 7 8 9
NB 857   50   44 156 9 133 110 82 167   20 86
P 183 7 3 17 105 7 4 13 14 10 3
Q 267 2 4 19 12 92 23 19 10 51 35
R 1187 26 43 91 6 22 96 252 205 88 358

In other words, there are 857 minor piece endgames in the database, of which 50 are classified NB0 (whatever that means). Of the four sub-classification schemes, the only explanation I could locate for this post was the scheme for Rook endgames, shown in the following diagram.

From CI's ECE 'Rook Endings'

That means of the 1187 Rook endgames, 358 are classified R9, 'not covered by another section'. The first page of each sub-class covered in the volume, R3 through R7, has its own sub-index for that section. There's a lot more that can be said here, so I'll come back to the CI resources in a future post.

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