Objective

Fill the grid with numbers so that all rules are satisfied:

• Each row contains every number exactly once.
• Each column contains every number exactly once.
• Each chain contains every number exactly once.

Some numbers are already given. Use logic to complete the grid.
Every puzzle has exactly one valid solution.

Grid and Numbers

• The board size ranges from 4×4 to 9×9.
• In an N×N grid, you use the numbers 1 to N.

The position of numbers is not ordered - only the rules below matter.

Rows and Columns

• Every row must contain all numbers from 1 to N.
• Every column must contain all numbers from 1 to N.

Chains

• The grid is divided into chains - groups of connected cells.
• Each chain contains exactly N cells.
• In each chain, all numbers from 1 to N must appear once.

Chains can have any shape, as long as cells touch by edges.

Given Numbers

• Some cells are prefilled.
• These numbers cannot be changed and serve as clues.

Progress

Start with smaller boards like 4×4 to learn the rules and patterns.
As you advance, move on to 5×5, 6×6, and larger grids for a greater challenge.

Train your logic, enjoy the chains, and have fun solving every puzzle!