How hard is Shikaku 6×6?

6×6 is medium difficulty. With 36 cells and numbers up to 36, you'll encounter more factor pairs and longer reasoning chains than 5×5. Typical solve time is 5-10 minutes.

How many rectangles are in a 6×6 Shikaku puzzle?

Usually 8-14 rectangles. The exact count depends on the puzzle design — larger numbers mean fewer, bigger rectangles.

What's the best strategy for 6×6 Shikaku?

Start with corners and edges (most constrained), then use factor decomposition for center numbers. A number like 12 in the center can be 2×6, 3×4, 4×3, or 6×2 — check which orientations fit without overlapping.

Shikaku 6×6 — The Sweet Spot

A 6×6 Shikaku grid has 36 cells — the perfect middle ground between quick 5×5 puzzles and challenging larger grids. Most players spend 5-10 minutes per puzzle, making it ideal for a coffee break.

▶ Play 6×6 Shikaku Now

Why 6×6 is the Most Popular Size

36 cells — enough complexity for satisfying "aha" moments
8-14 rectangles — diverse shapes without overwhelming
5-10 minute solve time — perfect for a focused session
Numbers up to 36 — introduces factor pairs like 12 (2×6, 3×4) and 18 (2×9, 3×6)

6×6-Specific Strategies

The "36 Check"

Before placing anything, add up all the numbers on the grid. They must sum to exactly 36. This quick sanity check catches transcription errors instantly.

Prime Numbers Are Anchors

In a 6×6 grid, primes like 5, 7, 11, 13 can only form 1×N or N×1 rectangles. A "7" must be a straight line of 7 cells — and in a 6-wide grid, it can only go vertically (7×1). These are your strongest constraints.

The "12 Fork"

The number 12 is common in 6×6 puzzles and has four possible shapes: 1×12 (impossible in 6×6), 2×6, 3×4, 4×3, 6×2. Always check which orientations fit the available space before committing.

Worked Example: 6×6 Puzzle

┌───┬───┬───┬───┬───┬───┐
│ 3 │   │   │ 2 │   │ 1 │
├───┼───┼───┼───┼───┼───┤
│   │ 6 │   │   │ 3 │   │
├───┼───┼───┼───┼───┼───┤
│ 2 │   │   │ 4 │   │ 2 │
├───┼───┼───┼───┼───┼───┤
│   │ 3 │   │   │ 2 │   │
├───┼───┼───┼───┼───┼───┤
│ 1 │   │ 2 │   │   │ 3 │
├───┼───┼───┼───┼───┼───┤
│   │ 2 │   │ 3 │   │ 1 │
└───┴───┴───┴───┴───┴───┘

1Mark all "1" cells. (0,5), (4,0), and (5,5) are instant 1×1 rectangles.

2Corner "3" at (0,0). Top-left corner, can go right (1×3) or down (3×1). Check: going right hits (0,3) which has a "2". So go down: (0,0)-(2,0).

3"6" at (1,1). Center area. Options: 1×6 (too wide), 2×3, 3×2, 6×1 (too tall). Try 2×3: (1,1)-(2,3). Check — (2,0) is taken by the "3", but (2,1)-(2,2) are free. Works!

4"4" at (2,3). Can be 1×4, 2×2, or 4×1. A 2×2 at (2,3)-(3,4) fits perfectly. Continue with remaining numbers...