Common Openings in Turn Zero

There are some commonly played openings in Turn Zero. Most of opening theory is dedicated to protecting against the f7 sac. All of the openings mentioned here will be played as white. Most openings will also be able to be played as black but with a tempo behind. The only exception is one of the e3 openings as show below.

The Mainline
The mainline is one of the first openings developed for Turn Zero and is the most beginner friendly.

As you can see, the mainline can be played with both white and black. However, black will be behind a tempo. This opening defends the common lines of the f7 sac, the diagonal on the f file and the triagonal from b3 to f7. The main issue with the mainline is that you cannot develop some of your pieces as they are either busy defending a square or are trapped by the pawn structure. This limits your attacking possibilities, which is the reason why many players stopped playing the mainline after a while. Some common threats that you have to worry about while playing the mainline is the defense of your b pawn. If your b pawn is not properly defended and your opponent attacks it with their queen, you can very easily lose the match.

The e3 Opening
The e3 opening is a very popular opening for many advanced 5D chess players. While it offers more opportunities for piece development and aggressive lines, it does not completely defend against the f7 sac. Therefore, people who play this opening have to take extra precautions to defend against the f7 sac. Common things that are played when people play this opening is Bd3 and h3. This is one of the openings that cannot be played symmetrically. While white can play e3 and then Nf3, black cannot play e6 first as white can easily punish black's weak f file by playing Qf3 and attempting to f7 sac. Therefore, black must play Nf6 and then e3 to not be in danger. Keep in mind that white can also play Nf3 first and then e3.

As you can see, the e3 opening is favored by many players because it saves a tempo compared to the mainline opening, while at the same time offers more opportunities regarding piece development and aggressive lines. One important thing to watch out is knight on the f file advancing to g5 or g4. This can lead to very dangerous situations. That is why pushing h3/h6 after the opening is crucial. Furthermore, if your opponent plays the mainline opening, it is also important to move your bishop to d3/d6 to stoop a potential bishop sac. Notice how a bishop on d3 will defend the f6 square. Some commonly played lines for the e3 opening are c4 to develop the queen, b4 to fianchetto the bishop and Ng5 to attack the f7 square. Furthermore, another variation of the e3 opening is playing Qf3 after e3. This opening is good for people who want to exile kings and or want to develop their queen early.

Resources
5D Chess Opening Book