Japanese Vertical Writing Generator

Understanding Tategaki and How Automated Tools Handle It

Vertical Japanese writing, or tategaki, runs right-to-left with characters stacked top-to-bottom. Books, newspapers, manga, and formal documents in Japan all use this format. Converting horizontal text to vertical manually is tedious work. You need to flip the reading direction, adjust line breaks, and handle punctuation correctly since some marks rotate differently in vertical mode. A Japanese Vertical Writing Generator takes your horizontal input and outputs properly formatted vertical text. Most work by processing character-by-character, reordering the layout grid, and applying CSS or SVG transforms depending on the output format you need. The best ones also handle ruby text, parentheses rotation, and the occasional line-break rule that Japanese typography demands.

How a Japanese Vertical Writing Generator Actually Works in Practice

Here is what happens under the hood. The tool reads your input string, splits it into individual characters, then replays them into columns that flow from right to left. Punctuation like commas, periods, and brackets gets rotated 90 degrees or repositioned depending on the typographic standard being followed. Line breaks in horizontal text are generally ignored or treated as column breaks. The output can be rendered as styled HTML with CSS writing-mode, an SVG image, or plain text with newline separators. I built and tested several of these tools over the years. Most generate decent output for simple prose. The ones that feel genuinely useful handle edge cases like long dash characters, mixed horizontal-vertical text blocks, and furigana overlay placement.

Common Pitfalls Nobody Mentions

One issue that consistently trips people up involves em dashes and ellipses in vertical mode. In horizontal Japanese, a long dash like stretches across the line. When rotated vertically, that same character becomes a tall pillar that breaks the visual rhythm. A proper tool will replace extended dashes with individual stacked marks or switch to the vertical-oriented em dash character (). Most cheap generators just leave the horizontal dash as-is, and the result looks sloppy on the first read. Another thing: line length calculation is not straightforward. In tategaki, a line is a column, and column height is determined by the number of rows you allocate. Set it wrong and you end up with orphaned characters at the bottom of a column or columns that are wildly uneven in height. The standard approach is to fix the number of rows per column and let the generator calculate how many columns you need, but very few tools expose this control clearly to the user.

My Workflow Using a Japanese Vertical Writing Generator

For most projects I use a tool called Verj and pair it with a quick CSS layer. Here is the process I go through. First, I paste the raw horizontal text into the generator. I select the output format as CSS-based HTML because it is the most flexible for web use. The tool spits out a block of markup with writing-mode: vertical-rl applied. I then open it in a browser and check the output against a reference document. Next I look for specific problem areas. The main one I always check is ruby text positioning. When furigana is attached to a character, the vertical generator needs to place the ruby on the correct side of the column. In left-to-right horizontal writing, ruby sits above the character. In vertical writing, it should sit to the right. Several generators I tested put the ruby below the character even in vertical mode, which is technically wrong and immediately noticeable to any Japanese reader.

After catching that error in my first batch of test output, I switched to manually correcting the ruby containers using inline styles. It added about ten minutes to a typical conversion, but the result was publishable. I have not found a single free tool that handles this correctly without adjustment.

When a Japanese Vertical Writing Generator Falls Short

These tools are not magic. They work well for straightforward text: novels, articles, product descriptions, simple documents. They struggle with anything that involves mixed scripts and variable-width justification. If your text contains a lot of English words interspersed with Japanese, the generator may wrap English terms awkwardly or rotate them in ways that look broken. CSS writing-mode handles mixed-direction text inconsistently across browsers, so even a perfect input file can render differently in Chrome versus Safari. For print-ready work, a generator is not sufficient on its own. You still need to run the output through a layout program like Adobe InDesign or Scribus, where you can fine-tune column balance, adjust hanging punctuation, and control the exact placement of decorative elements. I usually use a Japanese Vertical Writing Generator to get a first draft into vertical layout in about fifteen minutes, then spend another forty-five minutes in InDesign polishing the rest.

Which Tool to Use Depends on Your Output

If you need quick web-ready vertical text, try tools that output CSS writing-mode HTML. They render reliably in modern browsers and require no special fonts. If you need downloadable images or PDFs, look for generators that export SVG or support direct PDF output. Free tools like the ones at CodePen based implementations work for basic cases. Commercial options used by Japanese publishing houses tend to integrate directly with their existing workflows and handle the edge cases I mentioned above. The core limitation across every tool I have tried is justification control. Horizontal text justification in Japanese uses character spreading, which is relatively easy to automate. Vertical justification involves adjusting the spacing between columns, and most generators simply do not touch this. The text may look acceptable at a glance but will have uneven column spacing when you examine it closely. If that matters for your project, you will need to adjust the spacing manually regardless of which generator you start with.