Four-Player Chess/Common openings/1. h3/1...c7

Scandinavian Defence, 1...c7
Blue opens on the light squares. Yellow often responds with h12, creating immediate tension between the light-squared bishops.

Yellow's responses
Yellow has three main ideas: g12, h12 and h11.

Classical Scandinavian, /1...g12/
In this classical variation Red and Yellow usually develop their queens along the dark-squared diagonals to j4 or k5 and d10 or e11, respectively. This opening may also lead to Fool's Mate, should Green respond with the move l7 or k7.

Modern Scandinavian, /1...h12/
This move aims to challenge the bishop on the a6-i14 diagonal immediately. Red can follow up with either Qk5 or e3 to put a lot of pressure on the b5 square. A popular response is the move l10 for Green, leading to the Icystun-Rezacz defence. This is a high-class waiting move. In the case of Red playing Qk5, Green can answer with l7, challenging the active queen. In response to Qk5 Blue takes advantage of the green queen having the option to challenge Red. The main moves for Blue are c6 and Nc6. The move c6 is the most solid response, opening up the diagonal for the queen to coordinate with the green queen. This forces the red queen off the board, because the queen is pinned to a mate threat on Red's g1 square. The downside for Blue and Green is that Green has to concede the right to castle. Yellow often plays Nk12 to threaten Nxl10 next move, given that Red can deliver a check to Green with Bh2+. Therefore, Blue has to bring the queen out to defend Yellow's attacks on Green. The best square for the queen seems to be d9, since it gives the option to check Yellow on the l9 square, where the queen is also protected by the green pieces. This can be important if Red plays e3 and Bxb5. This opening is not easy to play and many games finish quickly. However, if both teams get out of the opening, a long grind may ensue and both sides have chances. Usually Red and Yellow will pick up the potentially strong bishop on n9 by means of Nk12-Nxm11-Nxn9.

Hypermodern Scandinavian, /1...h11/
This move is a counter against Green's idea of playing l10 on move 1. It was made popular by the Ukrainian grandmaster Dmitry Kononenko playing under the pseudonym valger. If Red now plays Qk5 and the queens are traded by virtue of Green playing l7, Yellow can then play g12 closing the a6-i14 diagonal to Blue and opening up the f14 bishop against Green. Since the king must recapture the queen, the green bishop is now undefended. Therefore, Blue and Green will suffer material loss, if they were to offer the queen exchange in this variation. The downside for Red and Yellow is that the e14-n5 diagonal is closed by the h11 pawn. This gives Blue the additional option of 2...Nb7, since 2...Bg12 now makes very little sense, given that it would be staring at the h11 pawn.