Kdp
29 posts on this topic.
21 October 2026 · 6 min read
How we prove a Binairo has one solution
A Binairo is two symbols and three rules. Generating one that follows them is easy; proving it is the only grid that does is the real work. Here is how.
18 October 2026 · 6 min read
How to make and sell Binairo books on Amazon KDP
A guide to making Binairo (Takuzu) books for Amazon KDP: pick a grid size, generate single-solution 0-and-1 grids, get the interior right, and upload.
17 October 2026 · 5 min read
Make a free printable sudoku (and turn it into a book)
Make and print a single sudoku free in your browser, no sign-up, then the one step that turns a puzzle into a graded book you can sell on KDP.
16 October 2026 · 7 min read
Why a picture nonogram almost never solves by pure logic
We drew 18 recognisable nonogram pictures. Every one had a single solution, but only one solved without a guess. The code, the numbers, and why.
14 October 2026 · 7 min read
How to make and sell nonogram books on Amazon KDP
A practical guide to making nonogram (picross) books for Amazon KDP: pick a size, generate single-solution picture grids, get the interior right, upload.
13 October 2026 · 6 min read
Word search books for kids on KDP: what sells
How to make a kids word search book that sells on Amazon KDP: big grids, short familiar words, no diagonals, bright themes. The choices that fit a child.
12 October 2026 · 8 min read
How to self-publish a children’s picture book
Self-publishing a picture book, step by step: word count, page count, illustration costs, consistent characters, print-ready files, ISBNs and launch.
10 October 2026 · 7 min read
Sudoku, word search or crossword: which to start with
An honest comparison of the three big low-content puzzle formats for KDP: how each is made, who buys it, and where each one is harder to sell.
6 October 2026 · 7 min read
KDP spine width and cover size: the exact formula
How to calculate KDP spine width and full-wrap cover size: the per-page paper multipliers, the bleed maths, three worked examples and the common mistakes.
4 October 2026 · 8 min read
How to make and sell maze books on Amazon KDP
A practical guide to maze books: picking a shape and an age, grading the book, provable answer keys, large print that means something, and the interior.
3 October 2026 · 6 min read
KDP sudoku interior specs: trims, margins and solutions
The trim sizes, margins, gutter, bleed and solutions layout a KDP sudoku interior needs to pass review, with the large-print grid numbers that sell.
1 October 2026 · 8 min read
How we make sure every sudoku has one solution
How our sudoku generator works: fill a grid, remove clues in pairs, and re-solve after every removal so each board has one answer. Real code and timings.
29 September 2026 · 9 min read
How to publish a paperback on KDP: the checklist
The ordered checklist for publishing a paperback on Amazon KDP: trim, paper, page count, interior and cover PDFs, metadata, pricing, proof and review.
23 September 2026 · 7 min read
Planner niches that sell on KDP
Over 70 planner niche ideas for KDP and Etsy, grouped by audience and layout, plus how to pick a niche and check demand on Amazon first.
23 September 2026 · 7 min read
Journal niches that sell on KDP
Over 70 journal niche ideas for KDP and Etsy, grouped by ruling and audience, plus how to pick a niche and check demand on Amazon first.
23 September 2026 · 9 min read
How to make and sell planners on Amazon KDP
A practical 2026 guide to publishing daily, weekly and monthly planners on Amazon KDP and Etsy: dated versus undated, page counts, interior rules and covers.
22 September 2026 · 7 min read
Journal and planner interior specs: trim, gutter, bleed
The numbers a journal or planner interior must hit at KDP, Lulu or IngramSpark: trim sizes, the gutter by page count, safe area, bleed and even page counts.
22 September 2026 · 8 min read
How to make and sell sudoku books on Amazon KDP
A practical 2026 guide to making sudoku books for Amazon KDP: a difficulty curve, single-solution grids, interior specs, a solutions section and upload.
22 September 2026 · 10 min read
How to make and sell journals and notebooks
A practical 2026 guide to publishing lined, dot grid and guided journals on Amazon KDP, Etsy, Lulu and print-on-demand: what sells, page counts, interior rules, covers, and the duplication trap that gets books removed.
22 September 2026 · 6 min read
Dated or undated? Which planner to publish
Dated planners sell for four months and expire; undated ones sell all year and never do. The trade-offs, the numbers, and why the answer is usually to publish both from one plan.
21 September 2026 · 7 min read
How to make and sell 3D spatial puzzle books on Amazon KDP
A practical guide to cube counting, draw-the-views and build-the-solid puzzle books: picking a type, grading the book, checked answer keys and the interior.
17 September 2026 · 6 min read
Large-print crossword books: a KDP niche worth publishing
Who buys large-print crossword, why the demand holds, what large print means for the grid and its 14pt clue list, and how to produce one for KDP.
17 September 2026 · 6 min read
KDP crossword interior specs: trim, margins and clues
The trim sizes, margins, gutter and clue-list layout a KDP crossword interior needs to pass review, with the 14pt clue floor and an 8.5 by 11 trim.
17 September 2026 · 8 min read
How to make and sell crossword books on Amazon KDP
A practical 2026 guide to making crossword books and publishing them on Amazon KDP: niches, grids, large-print clue lists, a solutions section and upload.
14 September 2026 · 7 min read
Word search book niches that sell on KDP
Over 90 word search book niche ideas for KDP, grouped by theme, plus how to pick a niche and check real demand on Amazon before you publish a single book.
14 September 2026 · 5 min read
Large-print word search books: a KDP niche worth publishing
Who buys large-print word search, why it stays in demand, what large print means for the grid and cell size, and how to produce one for KDP.
14 September 2026 · 6 min read
KDP word search interior specs: trim, margins and gutter
The trim sizes, margins, gutter and bleed a KDP word search interior needs to pass review, with the large-print numbers that actually sell.
14 September 2026 · 8 min read
How to make and sell word search books on Amazon KDP
A practical 2026 guide to making word search books and publishing them on Amazon KDP: niches, puzzles, interior specs, answer keys and upload.
14 September 2026 · 6 min read
Free vs paid word search generators: what gets published
An honest look at free online word search generators versus paid KDP tools, and what a generator actually needs before it can build a book you can sell.