Opening regulations are special rules that govern the setting of the first moves in a game. For renju regulated by the regulations, the first moves should be no more than five, for gomoku there is no such restriction.

After the introduction of fouls, after some time, as a result of active practice, it became obvious that fouls alone were not enough to equalize the chances. To solve this problem, the opening regulations were proposed.

Opening regulations with color choice and RIF

The first debut regulation in renju, which was used at the world championships (since 1989), was a regulation with a choice of colors. Its essence was as follows: the first player placed a black stone in the center, the second player placed a white stone in the central 3*3 square, then the first player placed a black stone in the central 5*5 square. After setting the first three moves, the second player had the right to change the color, i.e. he actually chose which color who would play until the end of the game. The one who turned out to be white in the end made the 4th move. The one who turned out to be black in the end had to offer two fifth moves to choose from (the so-called alternative fifths, in the first opening regulations – with a choice of color and RIF – their number was strictly equal to two). The player playing with white chose one of these two alternative fifths, made the sixth move, and then the game was played according to the usual rules. The rule with the possibility of changing colors is necessary to prevent the first player from making an opening in which Black would have a tangible strong advantage (otherwise the second player would simply change colors and play as Black). This is how the problem of equalizing chances was solved. Active practice with this opening regulation showed that it is more profitable for White to make diagonal openings, which is why after 1995 another opening regulation was proposed, which is called RIF (in honor of the International Renju Federation). Its only difference is that the second move (i.e. the white stone) is placed by the first player. That is, the first player who starts the game puts 3 stones at once: two black and one white (all with the same restrictions, the second move must be in the central 3 * 3 square, the third – in the 5 * 5 square). The rest remained the same as in the regulations with the choice of color.
The rapid development of the theory in subsequent years led to the fact that according to RIF, 11c was mainly played, known for its draw variation, and, less often, 3c, as in other openings with two alternative fifths, a win or advantage of one of the parties was found (in 13 openings, and also in 1d and 5d – white, in other openings – black). Despite this, the RIF regulations held out until 2008 (and even at the highest level, in the correspondence world championships), until a number of opening regulations that are relevant today were approved, which will be discussed below. The RIF opening regulations are almost never used in tournament practice at the moment, but they are used to train new players.

Yamaguchi Opening Regulations

Yamaguchi’s opening regulation is a logical continuation of the RIF, it was proposed by the Japanese player Yusui Yamaguchi. If two alternative fifths in RIF are not enough, then in Yamaguchi it is proposed to increase or decrease their number, depending on the openings, while the players themselves will choose the number of fifths. As in RIF, the first player places one of the 26 openings, but he also names the number of fifth alternatives that Black will place after move 4 (you can name any number from 1 to 221). The second player, as well as in RIF, has the right to reverse (i.e. change color and play black). The one who ended up being white makes 4 moves. After that, the one who ends up playing black must offer as many fifth alternative moves as the first player announced when setting up the opening. The one who plays white chooses one of them, makes the sixth move, and then the game proceeds according to the usual rules.
The obvious advantage of Yamaguchi’s regulation is that it significantly expands the number of playable openings compared to RIF.
Obvious disadvantages: as before, the 13th opening cannot be played, and the problem of the impossibility of getting away from the draw line 11c has not been solved. Moreover, as a result of the practice of this regulation, several more draw variants were discovered: 7v / 5v and 9v.
Yamaguchi’s debut regulation is currently the most popular (in particular, all world championships have been held according to it since 2009), but recently the question of abandoning the Yamaguchi regulation in favor of the more progressive Taraguchi-N and Soosyrva-N has been increasingly raised.

Debut regulations Soosyrv-N

This opening regulation (with a different number of maximum possible fifths) was proposed by two players – Swede Peter Jonsson and Estonian Ants Soosyrv. It is similar to the Yamaguchi regulations, but its main idea is that the number of alternative fifths is called by White after 4 moves. So, the first player places one of 26 openings. The second player has the right to change the color. The one who plays white puts 4 moves and calls the number of alternatives