# List of Tapa variants

There are hundreds of Tapa variants. Serkan has compiled a list of Tapa variations, including all of those that have appeared on his Tapa Variation Contests. Unless noted, the followings are extraction from the list. Base rule of Tapa is based on rules from WPC 2019 IB.

### Tapa Islands[edit]

Invented by Jan Mrozowski (Poland). Hybrid with Nurikabe, sometimes called Islands. First appeared on TVC IV.

Shade some cells so that all shaded cells are connected and no 2x2 square is completely shaded. Cells with numbers cannot be shaded. The unshaded numbers indicate how many of the neighbouring cells are shaded, and these shaded cells form a contiguous group. Moreover, each white region contains at most one clue cell. If there is a clue cell in a white region, one of the digits gives the size of that area.

#### Rule variations[edit]

- A puzzle from WPC 2018/Round 6, "Nurikabe Tapa", only featured single-numbered clues and required every white region to contain a clue cell, thus being closer to Nurikabe. Author of the puzzle was Jan Zvěřina (Czech Rep.)

### Alternative Tapa[edit]

Invented by Serkan Yürekli (Turkey) in 2011. First appeared on TVC VI.

Shade some cells so that all shaded cells are connected and no 2x2 square is completely shaded. Cells with numbers cannot be shaded. The numbers indicate how many of the neighbouring cells are shaded. Each number corresponds to a contiguous group of shaded cells, two such groups are separated by one or more unshaded cells. For each set of identical letters, only one must be shaded.

### Twilight Tapa[edit]

Invented by Nils Miehe (Germany) in 2010. First appeared on LMD portal.^{[1]}

Shade some cells so that all shaded cells are connected and no 2x2 square is completely shaded. Cells with numbers cannot be shaded. The unshaded numbers indicate how many of the neighbouring cells are shaded. Each number corresponds to a contiguous group of shaded cells, two such groups are separated by one or more unshaded cells. Similarly, the shaded numbers indicate how many of the neighbouring cells are unshaded.

### Tapa Line[edit]

Invented by Palmer Mebane (USA) in 2011. First appeared on Palmer's blog.^{[2]}

Shade some cells so that all shaded cells are connected and no 2x2 square is completely shaded. Cells with numbers cannot be shaded. The unshaded numbers indicate how many of the neighbouring cells are shaded. Each number corresponds to a contiguous group of shaded cells, two such groups are separated by one or more unshaded cells. Additionally, there may not be four consecutive shaded cells in any row or column.

(Example from WPC 2017 IB)

### Tapa Double Back[edit]

Invented by Bram de Laat (Netherlands) in 2011. First appeared on Bram's blog.^{[3]}

Shade some cells so that all shaded cells are connected and no 2x2 square is completely shaded. Cells with numbers cannot be shaded. The unshaded numbers indicate how many of the neighbouring cells are shaded. Each number corresponds to a contiguous group of shaded cells, two such groups are separated by one or more unshaded cells. Additionally, each region must be occupied by two separate segments of shaded cells.

(Example from WPC 2017 IB)

### Tapa Trimino[edit]

Invented by Rohan Rao (India) in 2011. First appeared on TVC VI.

Shade some cells so that all shaded cells are connected and no 2x2 square is completely shaded. Cells with numbers cannot be shaded. The unshaded numbers indicate how many of the neighbouring cells are shaded. Each number corresponds to a contiguous group of shaded cells, two such groups are separated by one or more unshaded cells. Additionally, shaded cells must be able to tile with L-trimino.

### Thermometer Tapa[edit]

Invented by Rohan Rao (India) in 2011. First appeared on TVC VI. The name is influenced by Thermometers.

Shade some cells so that all shaded cells are connected and no 2x2 square is completely shaded. Cells with numbers cannot be shaded. The unshaded numbers indicate how many of the neighbouring cells are shaded. Each number corresponds to a contiguous group of shaded cells, two such groups are separated by one or more unshaded cells.

The grid contains thermometers which can be completely used, partially used or completely unused. The mercury rises starting from the head (rounded end) to the tail, without skipping any segments.

### Hungarian Tapa[edit]

Invented by Zoltan Horvath (Hungary) in 2011. First appeared on TVC VII.

Place numbers in the given range into some cells so that all numbered cells are connected and no 2x2 square is filled with numbers. The wall should only be made up of the digits from the given range. Each row and column should contain the digits from the given range exactly once. Tapa clues indicate the sums of the separate blackened cell blocks in the neighbouring cells.

(Example (1-4) from WPC 2019 IB)

### Kakuro-Style Tapa[edit]

Invented by Anurag Sahay (India) in 2012. First appeared on Anurag's blog.^{[4]}

Shade some cells so that all shaded cells are connected and no 2x2 square is completely shaded. Cells with numbers cannot be shaded. The unshaded numbers indicate how many of the neighbouring cells are shaded. Each number corresponds to a contiguous group of shaded cells, two such groups are separated by one or more unshaded cells.

Additionally, clues in black cells represent the number of separate blackened blocks in the corresponding directions. For any direction provided with a clue, the separate blocks should be of different lengths.

(Example from WPC 2017 IB)

### Tapa Skyscrapers[edit]

Invented by Prasanna Seshadri (India) in 2012. First appeared on Prasanna's blog.^{[5]}

Shade some cells so that all shaded cells are connected and no 2x2 square is completely shaded. Cells with numbers cannot be shaded. The unshaded numbers indicate how many of the neighbouring cells are shaded. Each number corresponds to a contiguous group of shaded cells, two such groups are separated by one or more unshaded cells.

Additionally, numbers outside the grid show the number of separate wall segments visible in that direction. A segment of length n is taken as a skyscraper of height n. Skyscrapers of length n can block visibility of other skyscrapers of length n and below.

(Example from WPC 2017 IB)

### Twopa[edit]

Invented by Prasanna Seshadri (India) in 2013. First appeared on TVC XV.

Furthermore, in the given two grids, every clue must behave differently.

### Tapa Groups or Cells[edit]

Hybrid of Tapa and TapaQ. Invented by Christian Halberstadt (Germany) in 2014. First appeared on LMD portal.^{[6]} TapaQ was invented by Sebastian Matschke (Germany) in 2009.

Shade some cells so that all shaded cells are connected and no 2x2 square is completely shaded. Cells with numbers cannot be shaded. Each number has one of two meanings:

- The number indicates how many of the adjacent cells are shaded, and these shaded cells form a contiguous group, or
- The number indicates how many separate groups of shaded cells are adjacent.

Clues may conform to both meanings.

(Rules (modified) from WPC 2019 IB)

### Full Tapa[edit]

First appeared on WPC 2016/Round 4, "Full Classics" round. The idea was by Matej Uher (Slovakia).

Shade some cells to get a valid Tapa solution:

Shade some cells to create a continuous region of shaded cells. Numbers in the remaining (unshaded) cells indicate the lengths of consecutive shaded blocks in the cells neighbouring orthogonally and diagonally. If there is more than one number in a cell, there must be at least one white cell between the shaded blocks. Shaded cells cannot form a 2×2 square.

(Rules and example from WPC 2016 IB)

### Disguised Knights Tapa[edit]

First appeared on WPC 2017/Round 6. The puzzle was by Prasanna Seshadri (India).

Additionally, the Tapa clues also describe the 8 cells that are a knight step away from them, in the same spacing considerations as the usual 8 cells, including the fact that the cells going out of the grid do not factor in the spacing.

(Rules and example from WPC 2017 IB)

### LITS Tapa[edit]

Not to be confused with Tapa LITS. The additional rule is loosely based on LITS rules. First appeared on WPC 2018/Round 6. The puzzle was by Jiří Hrdina (Czech Rep).

Place some tetrominoes in the empty cells so that they form a continuous wall with no 2×2 regions. Tetrominoes of the same type cannot touch each other by sides. The hints indicate all the tetromino segments in the surrounding 8 cells in no particular order. Each segment is created by all the adjacent cells of the same tetromino type (rotation or reflection of the tetromino does not change its type).

(Rules (modified) and example from WPC 2018 IB)

## Appearances in the past WPCs[edit]

- WPC 2019/World Cup Round 1 (Hungarian Tapa) by Roland Voigt
- WPC 2019/Round 8 (Twilight Tapa) by Rainer Biegler
- WPC 2019/Round 11 (Tapa Groups or Cells - Hexagonal) by Christian Halberstadt
- WPC 2018/Round 6 (Tapa Islands) by Jan Zvěřina
- WPC 2018/Round 6 (LITS Tapa) by Jiři Hrdina
- WPC 2017/Round 6 (Alternative Tapa, Twopa, Tapa Skyscrapers, Thermometer Tapa, Kakuro-style Tapa, Disguised Knights Tapa, Tapa Line, Tapa Double Back) by Prasanna Seshadri
- WPC 2017/Round 6 (Tapa Trimino, Instructionless Tapa) by Rohan Rao
- WPC 2016/Round 4 (Full Tapa) by Matúš Demiger and Matej Uher

## References[edit]

- ↑ https://logic-masters.de/Raetselportal/Raetsel/zeigen.php?chlang=en&id=0000F0
- ↑ https://mellowmelon.wordpress.com/2011/07/29/puzzle-343/
- ↑ http://puzzleparasite.blogspot.com/2011/12/puzzle-70-tapa-double-back.html
- ↑ http://anuragthefirst.blogspot.com/2012/09/kakuro-style-tapa_3.html
- ↑ https://prasannaseshadri.wordpress.com/2012/06/17/puzzle-no-172-tapa-skyscrapers/
- ↑ https://logic-masters.de/Raetselportal/Raetsel/zeigen.php?id=0000QQ