Putting a puzzle PDF on a Kindle Scribe.

Over USB, plug the Scribe into a computer, open it as a drive, and drop the PDF into the documents folder. Eject it and the file appears in your library. This route leaves the file untouched, which is what a fixed-layout puzzle book needs.

The Send to Kindle desktop app does the same job over Wi-Fi. Install it on Windows or macOS, sign in, drag the PDF onto the window and pick your Scribe. The file goes up to Amazon and comes back down to every device on the account.

By email, send the PDF as an attachment to your device's own @kindle.com address, which is listed in your Amazon account under the device settings. Send it from an address you have approved in those same settings, and leave the subject line empty.

Do not put the word Convert in the subject line. That asks Amazon to reflow the PDF into Kindle text, and a nonogram is not text. The grid, the clue columns and the index links are all layout, and reflowing them destroys the puzzle.

Kindle software 5.19.2 brought pen annotation to USB-sideloaded PDFs across every Scribe generation. Before that, a PDF copied over by cable could be read but not written on, and only files that had passed through Send to Kindle accepted pen marks. If you have ever loaded a puzzle book by cable and found the pen inert, that is why.

So if your device is on 5.19.2 or later, the cable route gives you an untouched layout and a working pen. If it is on something older, update it, or use Send to Kindle until you do.

Once the pen works, a nonogram solves the way it does on paper. Fill a square with a short stroke, mark a known-empty square with a light cross so you do not work it out twice, and erase when a branch turns out wrong.

The Scribe's usable page is about 6.2 by 8.3 inches, or 1860 by 2480 pixels at 300 ppi. The Scribe edition of every RiddlePortal book is drawn at 446 by 595 points, which is that area almost exactly, so the reader has nothing to scale. The grid stays crisp and the clue numbers keep the weight they were given.

A book laid out for US Letter does not do this. Opened on a Scribe it is shrunk to fit, taking the clue digits down with it, and you end up pinching in and losing sight of the row you were working on. That is why every book ships as five separate files rather than one.

The pages are pure black-and-white vector, with no grey fills for e-ink to smear, and the tablet editions are linked in both directions: tap the index to reach a puzzle, tap Answer for its solution, tap Back to return to where you were. Those links live inside the PDF, which is one more reason to avoid the conversion route.