# Right-handed and left-handed rotation systems

Thread in 'Discussion' started by mrk_lch, 17 Jul 2020.

1. ### mrk_lch

Can someone explain to me what it means left-handed rotation system (GB Tetris) and right-handed (NES Tetris) rotation system? Is it because of the predominance of building along the left or right wall?

2. ### Guest

T, L, J, S and Z pieces are 3 columns wide when they spawn horizontally. There is no real middle for those pieces in a 10-wide matrix. So as a game designer you have to decide, whether you want to spawn them more towards the left side (3 columns empty on left side and 4 columns empty on right side) or more towards the right side (4 columns empty on left side and 3 columns empty on right side). The first choice is also called left-handed, and the second choice is also called right-handed. It's hard to get acustomized to different rotation systems. Let's say you want to drop a S or Z piece vertically two columns away from the left wall. In GB Tetris you would have to press left one time; in NES Tetris however you would have to press left 3 times in the same situation. That messes up your muscle memory.

Leaving the left-most column empty is indeed the better choice in GB Tetris, while leaving the right-most column empty is the better choice in NES Tetris. That is kinda related to left-handed and right-handed (stacking lower on the closer side means that you can burn lines more easily when in trouble) but other things can influence that as well. In GB Tetris the I piece rotates towards the left side which means the left side is closer for the I piece. In GB Tetris you can also make S- and Z-Spins, if you leave the left-most column empty (because they also rotate towards the left side). The situation is the opposite in NES Tetris: I, S and Z pieces rotate towards the right side. That means the right side is closer for the I piece and you can make S- and Z-Spins when leaving the right-most column empty.

mrk_lch likes this.
3. ### mrk_lch

This explanation is really excellent. Then I take advantage of your preparation and ask you one more thing. Do you think left-handed people have a tendency to build on the left side (i.e. focus on the left side and then leave the left column free to do tetrises there)? For example, I am right-handed and I have always operated on the right side especially at the beginning. I left the right column free and waited for piece "I" to make the tetris. Even today it is more natural for me on the right. Is it possible that for left-handers the same thing applies on the left?

4. ### Guest

I think people have the tendency to leave the right column empty and insert the I pieces there. I watched some GB Tetris videos and I would say the side choice is 50:50 even there (although mostleft column empty is slightly better). Dunno if this has something to do with your dominant hand (or dominant brain half). Another explanation would be that people read from left to right. This could make people fill the left side first.

It's also interesting that the first Russian versions used right-handed spawnings but spawnings became left-handed eventually. I think this is because coordinate systems start on the left side (so choosing the left side as a programmer is more natural).

mrk_lch likes this.
5. ### mrk_lch

I fully agree with your intelligent considerations. Thank you for clarifying this important aspect of the game.