The goal of the game is to occupy as many field squares as possible with your team’s chips by effectively using the possibility to put, move and replace the opponent team’s chips with your own chips. The game is over when all board squares are occupied with chips. The team that has more chips on the main 10×10 field (or 8×8) in the end wins.

Teams can consist of 1, 2 or 3 people. Playing 3×3 is a classic version.

The CTOR game provides no ‘first turn advantage’. If the games is played 1 vs 1, 2 vs 2, or 1 vs 2, the team which has to play first puts 1 chip, then the second team puts 2 chips. If the games is played 1 vs 3, 2 vs 3, 3 vs 3, the first team puts 1 chip, the second team puts 2 chips, then the first team can put 3 chips. After these moves, the game goes back to regular rules (see Table).

The game field consists of squares. Each square has its respective field coordinate represented by a unique number. On the 10×10 field, the squares bear numbers from 1 to 100; on the 8×8 field – from 1 to 64.

The field is a torus-shaped surface (doughnut) rolled out flat as shown in Fig. 1.

Squares along the field perimeter are auxiliary ones. They form an additional game field. They ‘duplicate’ squares of the main field on the other side. Fig. 2a shows a main square field (#5) and a corresponding additional square field.

Fig. 2b shows an example of a main field corner square (#8), which has three corresponding squares on the additional field.

There is a total of 4 squares of this kind on the main field: No. 1, 8, 57, 64, each having 3 ‘duplicate’ squares on the additional field (for 8×8 field).

All manipulations with chips are performed on the main field. If a chip is put onto an edge square (#4) of the main field, its ‘duplicate’ is put on the opposite side, on the additional field (Fig. 3a).

For side squares of the main field, one duplicate is put; for corner squares No. 1, 8, 57, 64, three additional duplicate chips for each one should be put (Fig. 3b).

Each turn consists of separate operations:

Put – putting a chip onto a free square of the main field and, if this is a color square, placing its duplicates on the additional field.

Move – moving a chip one square (#28) across the field in a horizontal or vertical direction (Fig. 4).

If the chip goes across main square fields marked in colour, its duplicate chip (#17) on the additional field should do the same (Fig. 5a).

The same rule applies to duplicates of chips on field corner squares (Fig. 5b).

Landing – two of your chips (#19, #12) are removed from the field, and one chip (#23) of yours is placed on the field instead (Fig. 6).

Replace – putting your chip instead of the opponent’s chip, if the latter is surrounded by at least five chips in any combination (in Fig. 7, a white chip is surrounded by 5 black ones).

Players perform operations (1-3) shown in the table below in turns, in any sequence. The Replace operation can be performed any time, upon completing one of the operations (1-3); the number of times is not limited. Players can skip operations if they believe it unnecessary at the moment. The team declares its turn completed and passes the turn to the opposing team.

• A player chooses a square field for his/her next operation and notes its number on a sheet of paper not revealing it to other team players.
• Then, all players of the team open their selected square field numbers simultaneously and perform the operation.
• If two or more team players choose the same square for their current operation (the same coordinate), only one of them performs all operations with a chip on this square.

Team 1 (number of players)	Team 2 (number of players)	Put	Move	Landing
1	1	2	2	1
2	2	2	2	0
3	3	3	3	0

In this version, field square coordinates noted beforehand are used to work out the team’s general strategy before the game starts.

Before the game, each team notes five numbers of ‘secret’ field squares. If, when making its turn, the opponent chooses a secret square, the team’s chip is put on this field instead of the opponent’s chip. Afterwards, this chip is treated as a regular one. The substitution is made before the team starts its turn.