Learn why a Nonogram cell is forced.

For each training line, the clue groups define a set of legal placements. A clue such as 3 1 means one run of three filled cells, at least one gap, then one run of one. The Coach generates every placement that obeys that order and the mandatory gap. It then removes any placement that conflicts with a known Fill or known X. If an unknown cell is filled in every surviving placement, that cell is forced Fill. If it is empty in every surviving placement, it is forced X. If different surviving placements disagree, the Coach must not call the cell forced.

The frozen source grid is still useful, but only for provenance and verification. It tells the generator which known Fill or X can be introduced without inventing a contradiction, and it lets the independent verifier confirm that every accepted forced move agrees with the original verified puzzle. The hidden grid does not decide the answer during training. This distinction is important because the same visible clue state should lead to the same forced move even if the source image were never shown to the player.

DailyBrainArc already contains 120 solver-verified Nonogram source grids: forty 5×5 puzzles, forty 10×10 puzzles and forty 15×15 puzzles. The classic game uses those sources for full-board play, Daily boards, autosave, Undo, Redo, Fill/X controls, optional mistake checking, Hint, clean clears and personal bests. V0.154 does not replace that bank and does not import an outside Picross corpus. Training lines are derived from every row and column of the same frozen bank.

That gives the Coach 2,400 source lines before technique filtering. Some lines support more than one teaching pattern, while others are useful for only one. The technique counts below are therefore counts of qualifying line states, not claims about 6,812 different full puzzles. Full-board Nonogram remains the place to solve the complete picture; the Coach deliberately isolates one deduction so the reason can stay visible.

Study explains the technique and records that you reviewed it. Drill 10 draws ten distinct tasks from the selected technique and clears at nine or more first-attempt correct answers. Mastery 14 draws fourteen distinct tasks and requires at least thirteen first-attempt correct. Across five techniques, those three steps create fifteen checkpoints.

A sixteenth checkpoint, Mixed Mastery 20, tests transfer across techniques. Every mixed session contains exactly four Full Fit, four Overlap, four Anchored Run, four Cross Split and four Completed Run prompts. The pass threshold is eighteen first-attempt correct. The fixed balance prevents a large technique pool from crowding out a smaller one and makes the meaning of a mixed score stable across deterministic seeds.

First-attempt scoring does not stop learning after a miss. You may keep working on the same prompt until you find a forced cell. The session remembers that the first choice was wrong, so a correction does not turn the miss into a perfect first try. This keeps checkpoint scores useful without punishing experimentation by hiding the explanation or ending the exercise.

A task can enter Weak Deductions after a genuine first-attempt miss or after you press Explain one forced move. An unseen task is never inserted merely because it belongs to a technique you have not mastered. If you miss and then correct the same prompt, the weak entry remains; the same-attempt correction proves that you can follow feedback, not that you recognized the deduction cleanly.

The weak entry can clear later when that exact task appears again and you solve it first attempt. Recommendation logic first looks for incomplete techniques with more saved weak items, then follows the earliest incomplete checkpoint. After all five technique tracks are complete, it recommends Mixed Mastery. Once the mixed checkpoint is clear, remaining Weak Deductions are recommended before speed practice. The queue is stored only in the local DailyBrainArc state and does not create a population rating, percentile or public profile.

First read the clue and count the minimum space it needs. If the run lengths plus required gaps exactly fill the line, test Full Fit. If there is extra space, imagine the earliest and latest legal placements and look for shared filled cells; that is the Overlap idea. Next use information already on the line. A known Fill can anchor a run and eliminate placements that cannot cover it. A known X can split the usable space and remove placements that cross it. Finally, when every clue-required Fill is already accounted for, close the line by marking the remaining unknown cells X.

On a full puzzle, row and column logic interact, so one forced mark often creates a new deduction in the crossing line. Logic Coach intentionally stops before that whole-board loop. It trains the local reason in isolation, then sends you back to Daily Nonogram or Unlimited Practice to apply the habit across an entire grid. That boundary also keeps the training claim modest: the five tracks cover common line-deduction patterns, not every named Nonogram technique or every possible full-board solving strategy.

Sprint 60 mixes tasks for sixty seconds and stores a local best solved count. It is a fluency transfer mode, not a shortcut through the checkpoint system. A fast sprint cannot automatically mark Study complete, pass Drill 10, pass Mastery 14 or clear Mixed Mastery. If a sprint exposes weak items, those tasks can still return to the deliberate review loop.

This separation avoids a common measurement problem: a speed score can improve because you become faster at familiar patterns, while mastery is supposed to reflect whether you can recognize the reason before feedback over a fixed set of prompts. DailyBrainArc keeps both signals but does not pretend they are the same ability.

Logic Coach does not measure IQ, clinical cognition, school-grade equivalence or expert Picross certification. It does not generate a global rating or population percentile. It does not claim that these five labels cover every deduction that an experienced Nonogram solver may use, and it does not claim that every forced cell has only one possible human explanation. The line-placement proof establishes that a move is forced under the visible constraints; a human solver may describe the same fact using different language.

The product also does not guarantee transfer to every arbitrary Nonogram found elsewhere. Its training authority comes from the project's frozen verified 120-grid bank. The useful claim is narrower: you can practice five transparent classes of line deduction, receive first-attempt scoring and exact weak-item review, and then transfer those habits back to the existing full-board game.