The 9th cycle of Kuksu Main Title Tournament is ready for sign-up!

Here’s the current draft of the rules:

**General Introduction**

The Kuksu Title Tournament is a tournament in league format.

**Rule 1: Hierarchy**

The hierarchy of the league is in the exponential function with base 2. Typically, we have:

Tier 1: League A

Tier 2: League B1, League B2

Tier 3: League C1, League C2, League C3, League C4

…

Tier n: League (A+n-1)1, …, League (A+n-1)2^(n-1)

**Rule 2: Promotion & Demotion**

Each league is a round-robin tournament consisting of 5 to 10 players. Every player plays one game against every other player in that league. Generally speaking,

**(2.1)** the player winning the top league, League A, will challenge the previous Kuksu title holder in the best-of-five title match to determine the new title holder. The loser of the title match will be placed in League A of the next cycle.

**(2.2)** the 2nd place in league A stays in league A for the next cycle. Other than League A, players who finish 1st or 2nd in their league will advance and compete in the next highest league in the next cycle;

**(2.3)** players who finish 3rd, 4th, or 5th compete at the same tier in the next cycle;

**(2.4)** players who come in 6th place or lower, will compete in next lowest league in the next cycle;

**(2.5)** if there are many players dropping off in the next cycle without enough new players with high rating, the players might be placed in a higher (but never lower) league than the default tier decided in (2.2)-(2.4);

**Rule 3: Tie breaker**

There are two kinds of tie breaker:

**(3.1)** System tie breaker:

The top three players in each league will automatically get the trophy from the system. (Disqualified players could not get the trophy)

**(3.2)** League tie breaker:

The tie among players with the same points will be broken first by the sum of defeated opponent’s scores (SODOS), then the league tier in the last cycle, then the league ranking in the last cycle, and lastly by overall rank. Players disqualified by timeout will not be considered disqualified since we only have one round. However, if you timeout too many games, you’re likely to be demoted using either tie breaker. This tie breaker will be applied in all cases except the trophy determination.

**Rule 4: Drop-out**

**(4.1)** **Every player (old or new) must register for the new cycle in the sign-up page** created about 1~2 months prior to the new cycle, in order to be considered in the league arrangement.

**(4.2)** When the registration period ends, invitations will be sent to the registered players and there will be a period of about 2 weeks for the players to accept the tournament invitation.

**(4.3)** As mentioned above, if you finish 1st or 2nd in your league you will compete in the next highest league in the next cycle. However, if you decide to skip and not play in the next cycle, you will probably not advance to the next highest league when do decide to resume the participation. Skipping a tournament results in “starting over again” if and when you ever do wish to resume.

**Rule 5: First-time player**

If you’re entering the league for the first time, the league you are seeded in initially is based upon both your rating and the needs of that particular tournament. For example, a player may be initially seeded in League B and yet have a higher rating than some of the players in League A. The reason is these players with the lower rating in League A may have earned their right to be there by placing high in League B in the previous cycle.

**Rule 6: Match setting**

Fischer: Clock starts with 1 week and increments by 1 day per move up to a maximum of 1 week.

No handicap, 6.5 komi, Japanese (or Korean) rules, conditional moves enabled.

**Rule 7: Number of Tiers**

Assume all the leagues are full (with 10 players), then Tier k could hold 10 * 2^(k-1) players, and Tier 1~k could hold up to 10 * (2^k - 1) players.

Therefore,

(1) if we have 5-10 players , k = 1, there will be only one tier (tier 1).

(2) if we have 11-30 players, k = 2, there will be 2 tiers.

(3) if we have 31-70 players, k = 3, there will be 3 tiers.

(4) if we have 71-150 players, k = 4, there will be 4 tiers.

(5) if we have 151-310 players, k = 5, there will be 5 tiers.

(6) if we have 311-630 players, k = 6, there will be 6 tiers.

(7) if we have > 630 players, that would be one of the largest go tournaments ever:)

**Rule 8: Number of groups and players in the bottom tier**

It’s quite possible that we do not have the exact number.

In general, assume we have n (10 * (2^k - 1) < n < 10 * (2^(k+1) - 1)) players, we’ll fill up the first k tiers with 10 * (2^k - 1) players and then, the remaining r = n - 10 * (2^k - 1) players will be divided into as many league groups as possible, while ensuring that the number of players in each group is between 5 and 10 and the total number of groups does not exceed 2^k.

If r >= 5 * 2^k, we could have all 2^k groups with at least 5 players, and the remaining (r - 5 * 2^k) players will be distributed to the 2^k groups as evenly as possible;

If r < 5 * 2^k, we could have at most Floor(r/5) groups with at least 5 players, and the remaining players will be distributed to these groups as evenly as possible.

Let’s say if we have 257 players, we’ll fill up the first 4 tiers with 150 players and then, the remaining 107 players will be divided into as many league groups as possible, while ensuring that the number of players in each group is between 5 and 10 and the total number of the groups does not exceed 2^4 = 16. In this case we have 107 >= 80 = 5 * 16, so we could have all 16 groups with at least 5 players, and the remaining 27 = 16 * 1 + 11 players could be distributed to the groups as evenly as possible, resulting in 11 groups with 7 players and 5 groups with 6 players.

In case the number of remaining players is 1~4 (e.g. if we have 314 players), we might exclude some players that are in the timeout status and show no evidence of returning, or invite some more players to make the grouping possible.

**Rule 9: Equivalence of rating when comparing between the old player and the new player:**

**(9.1)** We’ll describe it with an example: if one player drops out of the league from League A and we only have 9 players by default, one player from League B (including the demoted player from League A in the last cycle) or the new players (the players from lower leagues are also considered as the new players in this case) might be drawn to fill up League A. The 3rd to 5th place from League B will be awarded 300, 200 and 100 ELO ratings, and the 6th to 8th place from previous League A will be awarded 300, 200 and 100 ratings, when compared with the new players. The same process will happen sequentially from higher tiers to lower tiers.

**(9.2)** If you were in the disqualification status (due to e.g. timeout) in the last cycle, there will be no awarding points even if you are placed in the positions described in (9.1) using the League tie-breaker described in (3.2).

**Rule 10: Seeding Method**

Once the players in each tier are decided, they will be placed using the snake seeding method according to their overall ELO rating.

**Grouping Algorithm Overview:**

-Input: Names of registered players with the current overall ratings, the tournament result (including the player name, league tier, league rank) from the last cycle.

-Output: The arrangement of the new league.

This system will be too complicated if it’s done manually. @Leira and I will try to make the system run automatically using the API.

This is the first draft of the system and any helpers, suggestions and comments are welcome:)