15×15 Picross Online — 225 Cells, Six Difficulty Levels

Fifteen rows, fifteen columns, 225 cells. The 15×15 is the platform's immersive large-format grid — a size where even Easy puzzles take 20–35 minutes, where pixel art reaches portrait-quality detail, and where the 30-line constraint network demands a systematic, deliberate solving approach from the first pass. Choose your difficulty and commit to the session.

Choose Your 15×15 Difficulty

→ 15×15 Easy — high-overlap clues, immersive sessions, richly detailed pixel art

→ 15×15 Medium — multi-block clues, sustained 30-line cross-referencing

→ 15×15 Hard — full arrangement enumeration across 225 cells

→ 15×15 Expert — hypothesis technique across a 30-line network

→ 15×15 Extreme — extended multi-cycle hypothesis solving across 225 cells

→ 15×15 Evil — nested hypothesis chains at maximum 15×15 complexity

What Makes 15×15 Different

Sessions with real weight. At 15×15, even Easy difficulty produces a 20–35 minute solving session. The format naturally selects for a more deliberate, focused approach than smaller grids — players who reach 15×15 typically do so because they want a longer, more immersive experience rather than a quick puzzle. Hard, Expert, and above become multi-hour commitments that are better suited to a dedicated session than a casual break.

Pixel art at portrait quality. At 225 cells, Picross images reach a resolution where complex subjects — faces with distinct features, detailed animals, scenes with multiple elements — can be represented with genuine visual clarity. The reveal at 15×15 is among the most satisfying on the platform and is a meaningful reason why players invest in the longer solving sessions the format requires.

Thirty lines to manage simultaneously. The 30-line constraint network at 15×15 is a significant step beyond the 24 lines of 12×12. At this scale, informal line tracking becomes genuinely unreliable — the probability of missing a line in a pass or losing track of which high-slack lines have been updated is high enough to cause consistent artificial dead ends. Active notation of line processing status is necessary, not optional, from Easy difficulty upward.

15×15 Overlap Analysis — Key Numbers

With a 15-cell line, these results define the practical overlap threshold:

Clue "15" → full line filled. Zero slack.

Clue "14" → slack 1 — cells 2–14 always filled. Thirteen confirmed cells.

Clue "13" → slack 2 — cells 3–13 always filled. Eleven confirmed cells.

Clue "12" → slack 3 — cells 4–12 always filled. Nine confirmed cells.

Clue "11" → slack 4 — cells 5–11 always filled. Seven confirmed cells.

Clue "10" → slack 5 — cells 6–10 always filled. Five confirmed cells.

Clue "9" → slack 6 — cells 7–9 always filled. Three confirmed cells.

Clue "8" → slack 7 — cell 8 only always filled. One confirmed cell — the minimum productive overlap result.

Clue "7" → slack 8 — zero overlap. Cross-referencing required before any cell can be confirmed.

Clue "8 6" → minimum span 15, slack 0. Forced: cells 1–8 filled, cell 9 empty, cells 10–15 filled.

Clue "7 7" → minimum span 15, slack 0. Forced: cells 1–7 filled, cell 8 empty, cells 9–15 filled.

Clue "5 5 3" → minimum span 15, slack 0. Forced: cells 1–5, gap, cells 7–11, gap, cells 13–15.

Where 15×15 Sits in the Full Progression

15×15 sits between 12×12 and 20×20 — six additional lines on each axis compared to 12×12, 81 more cells, and a noticeably longer session at every difficulty level. Players who have completed 12×12 Hard and 12×12 Expert reliably are well prepared for 15×15. The technique is unchanged; the scale requires more systematic habits.

From 15×15, the progression continues to 20×20 Picross — the platform's extended large-format grid where solving sessions approach and exceed half a day at the highest difficulty levels.

Stuck on a specific puzzle? The 15×15 Solver identifies your next step from the current clue state.