---
title: "KDP bridges book maker: generate once, export every trim"
description: "Generate a whole bridges book across a difficulty curve, then export every KDP trim at 300 DPI. Unlock a project once for $4.99 and re-export forever."
source: "https://www.oncebooks.com/kdp-bridges-maker"
---

Publisher Studio

# The KDP bridges maker

Generate a whole graded bridges book, then export it at every KDP trim, print-ready at 300 DPI. Make one puzzle free in your browser, unlock a full project for a one-time fee, and export unlimited formats forever.

[Open Publisher Studio](https://app.oncebooks.com/publisher-studio/bridges)[Make one free first](https://www.oncebooks.com/tools/bridges-generator)

$4.99 once per project. Unlimited exports, every trim. No subscription.

## Every puzzle joins up exactly one way

The first network on a board is a spanning tree, which always pins itself. But if every answer were a tree, a reader would know no loop can ever close, and that is half a solve given away. So every bridge beyond that tree is added one at a time and kept only while the solver still proves the board joins up a single way. Added blindly, most of them make the board ambiguous.

## Every KDP trim, 300 DPI

Pick any of KDP's 17 trim sizes, from 5.06 by 7.81 up to 8.27 by 11.69, with correct margins and gutter. The single interior file you upload passes KDP review.

## Generate once, export forever

One project unlocks for $4.99. After that, re-export any trim, any time. No monthly subscription and nothing to cancel.

## How it works

1. Try a free puzzle. Use the free generator in your browser to make one bridges puzzle and its finished network, so you can see the output before you commit.
2. Pick a difficulty curve. In Publisher Studio, choose how many puzzles you want at each grade, from a seven by seven board up to a fifteen by fifteen, and the studio generates the whole graded book.
3. Choose your KDP trim. Pick a trim size. The interior is sized with the right margins and gutter for the page count so it passes KDP review.
4. Unlock once, export any size. Unlock the project for $4.99, then export the print-ready interior and solutions PDFs at any trim, as often as you like.

## Free tool or full studio

The [free generator](https://www.oncebooks.com/tools/bridges-generator) makes one printable puzzle to try the engine. Publisher Studio is where you make a book to sell.

| Free generator | Publisher Studio |
| --- | --- |
| One puzzle and one answer page | Hundreds of graded puzzles with a solutions section |
| Large print only, printed from the browser | Every KDP trim, 300 DPI, print-ready PDFs |
| One board at a time | A graded curve from a 7×7 board to a 15×15 |
| Nothing is saved once you close the tab | A durable project, re-export any size forever ($4.99) |

## One price, per project

$4.99

Paid once. Export unlimited formats, forever.

- Print-ready 300 DPI interior PDF
- Separate solutions PDF
- Every KDP trim size and format
- Re-export any size, any time

[Open Publisher Studio](https://app.oncebooks.com/publisher-studio/bridges)

[Comparison Once Books vs Book Bolt A purpose-built puzzle-book maker you pay for once, versus an all-in-one KDP suite on a subscription.](https://www.oncebooks.com/compare/book-bolt)

## Questions

**How much does it cost?**

A project unlocks for $4.99, paid once. After that you can export the interior and solutions PDFs at any KDP trim, as many formats as you like, forever. There is no subscription.

**What do I get when I export?**

One print-ready 300 DPI interior PDF, with the answers at the back, sized for the KDP trim you choose. That interior is the single file you upload to KDP. You also get a separate solutions PDF.

**Are the puzzles guaranteed to have one solution?**

Yes, and it is the thing to check when you compare bridges books. Every board is proved to join up exactly one way before it enters the book, and every bridge on it was checked against that proof as it was added.

**How are the bridges drawn?**

On no grid at all, which is how printed Hashiwokakero is drawn: islands and their bridges on white. A double bridge is two lines with a clear stripe of white between them, wide enough to read at the smallest trim we sell, because one bridge or two is the entire answer on any pair. The bridges are drawn under the islands, so no line ever crosses a number.

**Is it the same as a maze?**

No. Nothing is traced through a passage and nothing is added up: the numbers count bridge ends, and the work is deciding which islands join and how many times. It sits closest to the puzzles where a shape is worked out from counts, so it suits a nonogram audience that would rather draw lines than shade squares. We publish both.

**Can I try it before I pay?**

Yes. The free bridges generator makes a real 2-page puzzle in your browser with no sign-up. The unlock is only for a full multi-puzzle project you plan to publish.

**Can I sell the books I make?**

Yes. The exported interiors are yours to publish and sell on Amazon KDP or print yourself. The per-project unlock covers unlimited exports of that project.