Jellyfish is an extension of X-Wing and Swordfish, by considering 4x4 grid instead of 2x2 or 3x3, respectively.
The same logic as in Swordfish, applies here. If we place any candidate from the 4x4 grid, the remaining candidates form a Swordfish,
so we can eliminate all other candidates from the grid rows or columns, depending on the configuration.
In general, Jellyfish occurs very rarely and we have only found 2 such occurrences in our set of 30 000 tested boards.
This is an almost perfect Jellyfish, with the only exception of H2, which has a value. The Jellyfish is configured by rows and the eliminations occur in the corresponding columns.
Hey there and welcome to our Learn Section!
If you are new to our website, please check out the How To Play section. It will introduce you to
the various tools and options used in our Web Platform. The section also contains interesting articles on
grading and generating our sudoku boards.
We are ordering our boards into the following difficulties - Very Easy, Easy, Medium, Hard,
Extreme and Impossible. The first three include the most basic strategies, which are a good point
for Sudoku Beginners to start at.
The last three include, among others, various Wings, Colourings and -Fish strategies which are often used by
advanced Sudoku players.
One great feature in our website is our Solver which can be used to Learn Sudoku on the go.
If you are stuck on a Hard Sudoku board, you can use the solver to grade it and show
you a step-by-step solution. The "Load in Solver" option is very useful and available for every example in our
Learn section.
For any questions, requests or recommendations, feel free to use the online contact form at the top of each page.
Happy learning! :)