NCS Rating regulations

1.Purposes of the NCS Rating

(1) To appropriately quantify match results of players who participated in the national tournaments.
(2) To be used to determine starting positions for the national tournaments, to award national titles and to select qualifying players.
(3) NCS issues two types of rating: Standard* and Rapid*.

2.NCS-registered clubs

(1) Tournaments reported for rating purposes must be organised by the NCS or NCS-registered clubs and be run in a fair manner by NCS annual members.
(2) Players who attend tournaments reported for rating purposes must have the NCS membership, including one-time tournament membership.
(3) All FIDE official tournaments shall be played according to the FIDE rules. In addition, the NCS must be notified at least two months prior to the event.

3.Rating calculation period and renewal fees

(1) The organizer must submit a rating report to the NCS after a tournament or meeting. For the FIDE official events, the organizer must submit, in addition to a rating report mentioned above, a prescribed TXT file to the NCS within 5 days.
(2) Rating calculation period starts on the 21st day of each month and ends on the 20th day of the following month. NCS calculates ratings for each calculation period and publishes new ratings on the first day of two subsequent months after the month in which rating calculation period started. (i.e. NCS calculates ratings incorporating match results from January 21 to February 20 and publishes new ratings on March 1 as rating for March.)
(3) Rating renewal fees to be paid by the club organizer are JPY200 per player. For tournaments organized on a periodic basis, there is no need to pay the rating renewal fees twice for the same player. (i.e. If Player A and B participates weekly tournaments hosted by Club C, the fees are JPY 400 for two players regardless of number of weeks they have participated.)
See: Bank Account Information
(4) If a payment of the rating renewal fees is not confirmed by the end of the month, or if a player fails to pay the membership fee, the match results may not be counted for the rating purposes.

4.Reporting procedures

(1) A rating report shall include a, b and c below. Whenever possible, use of Swiss Manager or reporting files provided by the NCS is encouraged.
a. Name of a tournament, date/time, venue, name of the person in charge of the tournament, type of game (standard or rapid)
b. NCS ID number and name in the Roman alphabet
c. Match results (white romanized name, result, black romanized name)
(2) If the pairing program Swiss Manager is used, uploading to and notifying the NCS of the upload can replace a rating report mentioned in the preceding paragraph.
(3) Player’s names are spelled in the Roman alphabet in the same way as FIDE does: family-name-first order and without a comma in between.
(4) If it was a player’s first official tournament or a player without ID, the player’s name in Kanji, date of birth, email address (any other available information) should be included.
(5) In a standard game, each player has at least 60 minutes, based on 60 moves. However, if it is not a FIDE official tournament, a game of at least 45 minutes can be deemed to be a standard game. Where there is no mention of type of games, they are calculated as rating report of standard games.
(6) A rating report for regional qualifying tournament of the national tournaments should include the names of qualified players.

5.Calculating the ratings

(1) C is the change and is calculated per game by formula: C = (R – PD) * K
• R is the result and a win gives 1 point, a draw 0.5 points and a loss 0 points.
• K is the development coefficient. The larger K is, the greater variation in a rating. The K for standard and for rapid are deemed different. Normally, the K is 20. For an unrated (UR) player whose cumulative number of games is below 18, or a player who is aged below 18 and has rating below 2400, the K is 40. For a player who has ever achieved a rating of 2400 or more, the K is 10.
• PD means the scoring probability and it is given from H or L shown in the table below depending on each other’s rating difference. (see Table 1 below)
• For example, Player A (Rating: 1600) and Player B (Rating: 1800), both of whom have the K=20, played a game. Since the rating difference is 200, the H is 0.76 and the L is 0.24 as shown in the Table 1. In this case, since the Player A’s rating is lower than Player B’s, PD is L=0.24. If the Player A wins, the change (C) is calculated as (1 – 0.24) * 20 = 15.2. If the Player A loses, it is calculated as (0-0.24) * 20 = 4.8.
(2) All the C values during one rating calculation period are added up and the total value is rounded to the nearest whole number. The new rating is calculated by adding this total and the current rating value.
(3) Unplayed games and games between UR players are counted as zero and not calculated in the rating.
(4) If the rating difference is 400 or above, it is always calculated as 400.
(5) The lowest NCS rating is 400.

6.Unrated players

(1) Players without NCS standard rating will take over the rating and the K in the following orders: ①NCS Rapid ②FIDE Standard ③FIDE Rapid ④FIDE Blitz
(2) Players without NCS Rapid rating will take over the NCS Rapid rating and the K in the following orders: ①NCS Standard ②FIDE Rapid ③FIDE Standard ④FIDE Blitz
(3) Players whose rating cannot be determined with (1) and (2) above are called unrated (UR) players and the rating is zero. The initial rating is calculated when a UR player whose cumulative number of games becomes 5 or more. The K is 40 for the first 18 games. This rating shall not be used for qualification examinations.
(4) The initial rating for a UR player will be derived by FIDE calculator.
(5) Where a UR player played five games or more without any losses or wins, the rating will be determined in consultation with the NCS Rating Department with reference to the value calculated by the FIDE calculator.
(6) Where a UR player plays five games or more, including a game against another UR player, the rating will be determined, in consultation with the NCS Rating Department, with reference to the value calculated by the FIDE calculator assuming the unrated opponent has the rating of 1000.


(1) NCS and its recognized clubs must deal with personal information with utmost attention.
(2) Any case that is not stipulated in this rules shall be processed in consultation with the NCS Rating Department with reference to FIDE Rating Regulations.
(3) These rules shall be revised with approval of the NCS Board of Directors.
Revisions List
Initial version issued on February 5, 2019
Revised on May 11, 2019 (effective on June 1)
Revised on August 31, 2019 (effective on September 1)
Revised on March 31, 2020 (effective on May 1)
Revised on January 31, 2021 (effective on February 1)

Table 1

(8.1b on FIDE Rating Regulations)


*Standard: the total time per player for a 60 move game is at least 60 minutes
*Rapid: the total time per player for a 60 move game is more than 10 minutes but less than 60 minutes
*Blitz: the total time per player for a 60 move game is 10 minutes or less (If it is not a FIDE official tournament, a game of at least 45 minutes can be deemed to be a standard game ! please refer to 4(5) above)