MultiSimultaneous Games

Following up on a discussion between Chris, cronin, LGSam, and others at KGS, in the context of Simul At KGS

In a simul, a player hosts a game and takes on many players at once (N vs 1).
An interesting twist on that would be having every player play also everyone else at the same time (N vs N).

While this is not currently possible on any of the KGS clients^[1][2], as of May2020, perhaps it is possible to make it happen with a workaround. The idea is to use several accounts, on several clients/devices ^[3], with a certain number of players hosting simultaneous games, and the rest joining the challenges. The abundance of clients makes it theoretically possible to use even just one device; see the reference table listing which client supports which kind of game, at the bottom of the page^[1].

Table of contents Example setups Example with three players: A, B, C Pairings Visual aid Combinations Number of accounts required Example with four players: A, B, C, D. Example with five players: A, B, C, D, E Generalized rules Reference: client support [1]

Example setups

Example with three players: A, B, C

note: players are indicated by a letter+number (e.g. A0) to refer to a specific account - in the example: A0 is 'player A, first account'; A1 is 'player A, second account', ...

Pairings

• board 1: A0, C0
• board 2: B0, C1, A1

That is:
player A hosts a normal game on board 1, and is challenged by player C.
player B hosts a Simul on board 2, and both player A and player C challenge them (both with their second account).
This means player B can use only one account (but needs to host a Simul); players A and C both need to use two accounts.
One of the players (player C) doesn't need to host any game.

Visual aid

note: applicable clients are indicated in curly braces

+-------------+               +-------------+
|             |               |             |
|  Player A   |  direct game  |   Player C  |
| {CG/G/S} A0 +===============+ C0 {*}      |
|             |               |             |
| {CG/A}   A1 +---+      +----+ C1 {CG/A}   |
+-------------+   |      |    +-------------+
                  |      |
                  |      |
                  S I M U L
               +-------------+
               |     B0      |
               |    {CG}     |
               |             |
               |  Player B   |
               |             |
               +-------------+
Legend:
CG - CGoban            G - GoUniverse
A - Android client     S - ShinKgs

Combinations

Boards and combinations can be laid out in table format; each player can consult their column to figure out which games they have to host, indicated by a subscript "h". When there is no entry, it means their opponent is going to host the match; the board number can be derived from the transposed cell (seek the entry on the player's row at the opponent's column).

Number of accounts required

AA - this player needs to host a game
B - this player needs to host a simul
CC

Example with four players: A, B, C, D.

Player B and C login from the Java client and host the Simul from their main account.
Player A hosts a normal game.
Player D hosts no game and challenges the other players on their boards.

Pairings:

• board 1: A0, D0
• board 2: B0, A1, C1, D1
• board 3: C0, A2, D2

Number of accounts required:
AAA - this player needs to host a game
B - this player needs to host a simul
CC - this player needs to host a simul
DDD

Example with five players: A, B, C, D, E

Pairings

• board 1: A0 E0 D1
• board 2: B0 E1 A1 D2 C1
• board 3: C0 E2 A2 D3
• board 4: D0 E3

Number of accounts required:
AAA - this player needs to host a simul
B - this player needs to host a simul
CC - this player needs to host a simul
DDDD - this player needs to host a game
EEEE

Generalized rules

• All players have to host a simul, except for two
  • one player will not have to host any games at all, they just find and challenge the existing games opened by the other players;
  • one player can host a normal challenge, and not a simul. This gives them the freedom to use any client, because the pairings require them to only play one opponent on that board;
• The number of accounts needed in a N player game is, for players ``(1, 2, ..., N)``, as follows: ``(1, 2, ..., N-1, N-1)`` - so the players will need ``N-1`` accounts (at most), with one player needing only one account.

Which means:
three players: need (1, 2, 2) accounts;
four players: need (1, 2, 3, 3) accounts;
five players: need (1, 2, 3, 4, 4) accounts;
and so on and so forth.

Reference: client support [1]

[2] also, the Java client is the only one that can host Simultaneous games
[3] or, alternatively, logging in and out of the same client with different accounts