Jstris

Jstris
Jstris icon
Developer(s)	jezevec10
Platform(s)	Web
Release	December 6, 2014
Gameplay info
Next pieces	0-5
Playfield size	10 × 20
Hold piece	Configurable in custom room settings, on by default
Hard drop	Yes
Rotation system	SRS, ARS, C2, O-spin

Jstris is a browser game created by jezevec10 and released on December 6, 2014. It is one of the unofficial online Tetris games to be playable on a browser.

Gameplay

The game uses modern guideline rules, such as holding pieces, SRS rotation system, etc.. Players are able to create their own rooms and change gameplay rules for that room such as changing previews, modifying the attack table, making it a team room, and more.

Modes

These modes can be selected by selecting each mode from the Play drop-down menu on the top bar.

• Live: This is a multiplayer mode where multiple players can battle against each other and send garbage. The last player standing wins.
• Sprint: The player is given a choice to clear 20, 40, 100, or 1,000 lines in the fastest time.
• Cheese: In Cheese, one player must clear all of the garbage lines as fast as possible. The number of lines to clear is selectable from 10, 18, and 100 lines. An infinite option is available, but since it is endless, there is no leaderboard for it.
• Map Downstack: Players will need to clear all the map blocks and/or get a PC finish depending on the settings the map has.
• Survival: In Survival, the player must survive for as long as they can while garbage lines rise at a rate of 1 line per second.
• Ultra: The player has 2 minutes to get the highest score.
• 20TSD: The player must perform as many T-Spin Doubles as possible. Despite the title 20TSD, the player can continue doing T-Spin Doubles even after completing 20 of them. The game ends automatically by either clearing a line that is not a TSD or blocking out.
• PC Mode: The objective is to complete as many perfect clears in a row as possible. Both 4-line PC and 2-line PCs are accepted. The game will end when a player fails to complete a PC in 10 pieces or stack higher than (4-line clears after last PC) height.
• Bots: The player can battle against one or more bots selected by user. Available bots are: Freybot, Dellacherie, ColdClear and MisaMino.
• Free Play (Also known as Practice in the drop-down menu): A training mode.

Additionally, special rulesets can be applied:

• Big Mode: All pieces are quadrupled in size, mimicking playing in a 5 × 10 field. Line clears are checked like they would be on a normal board, however. In this ruleset, the player can only play 40/100/1000 line Sprint and Free Play.
• Pentomino: All pieces become pentominoes. In this ruleset, the player can play all Sprint modes, 10-line or infinite Cheese Race, Ultra and Free Play.
• MPH: No previews nor Hold are available, and the randomizer is set to "Classic" (which is actually memoryless). In this ruleset, the player can play all Sprint modes, all Cheese Race modes, Ultra, 20TSD, PC Mode and Free Play.

Rooms

All players entering the site are directed first to the Default Room. However, if the player has an account and has an average 10-game APM of less than 20 as well as less than 30 hours of gametime played, they will be directed to the New players room instead. 5 built-in rooms are available:

• 1v1 Room
• Map Room
• Default Room
• Slow Room - available to everyone, but the players can't drop pieces faster than 1.5 PPS. Additionally, the room has 500 ms of line clear delay.
• New players - available to players with 10-game APM below 20 and less than 30 hours of game time. NoFW is active, so 4-wides backfire to the player.

In cases where the Default Room and/or New players room is full, Overflow rooms will be automatically created. These rooms have a max capacity of 7 players and are divided (based on APM) into:

• Fast - Any registered player can join.
• Medium - For players with APM between 20 and 50.
• Slow - For players with APM below 20.
• Guest - For those without an account.

Details

Buffer zone

Above the board, Jstris uses a single-row buffer zone, extending the effective height of the playfield from 20 to 21. Blocks that are in row 21 will reappear on the board once stack gets lowered. However, rows 22 and above are not a part of the buffer zone, meaning that blocks in such rows will vanish and won't reappear after the stack gets lowered. Jstris' buffer zone is also not solid, so pieces won't collide with blocks in buffer zone. This can be taken advantage of in some modes, such as 20TSD:

S piece is active	S piece locked - the block above row 21 vanished	L piece is active. Note that it overlaps the part of the S piece.	L piece locked

Pentominoes

Pentominoes in Jstris follow the Super Rotation System kick table:

• I5 piece mirrors the SRS kick table for the I-piece,
• Every other pentomino mirrors the SRS kick table for Z, S, L, J and T-pieces.

This notably causes some off-the-wall kicks to fail:

Attempt to rotate L -> 0	Test 1	Test 2
Test 3	Test 4	Test 5 All tests failed

O-spin

O-spin is a meme rotation system in which O-spin Triples and O-spin Quadruples are possible. It also allows for many unconventional spins, because its kick table contains 15 kicks, as opposed to SRS which only contains 4 kicks.

Wall Kick Data for O-spin Rotation System

	Test 1	Test 2	Test 3	Test 4	Test 5	Test 6	Test 7	Test 8
Any rotation	( 0, 0)	(-1, 0)	( 1, 0)	( 0,-1)	(-1,-1)	( 1,-1)	(-2, 0)	( 2, 0)
	Test 9	Test 10	Test 11	Test 12	Test 13	Test 14	Test 15	Test 16
Any rotation	( 0,-2)	(-1,-2)	( 1,-2)	( 0, 1)	(-2,-2)	( 2,-2)	(-3,-3)	( 3,-3)

Examples:

	Rotate CW	Passes test 16 T-spin Triple

	Rotate CW	Passes test 10 L-spin Triple

O-pieces however are transformed when rotated in a certain way:

1. O-piece transforms into an L piece and then into a T piece to perform an O-spin Triple. This is a reference to a YouTube video, in which a player performs an O-spin Triple in Tetris Friends.. The setup shown below won't work when mirrored.

T-spin Triple setup	Rotate CW	Rotate CW	O-spin Triple

2. The O-piece transforms into a 4 × 4 O-piece to perform an O-spin Quadruple.

	Rotate CCW	O-spin Quadruple

External links

• Play Jstris
• Original forum thread