Japanese SEO: Scripts, Search Habits and Site Setup

Q: Should I use hreflang ja or ja-JP?

Language alone, ja, is normally enough. Use ja-JP only if you have a reason to separate regional variants.

Short answer: Japanese SEO starts with real Japanese keyword research, not translated English terms. Searchers mix kanji, hiragana, katakana and Latin letters, and often type the same idea in several forms. Write in a tone that fits your audience, use UTF-8 and a proper language declaration, plan fonts and page speed for large character sets, add hreflang for the Japanese version and localize prices, dates, payment and trust signals.

Japan is one of the largest and most demanding online markets, with high mobile use and strong expectations about service and detail. A website that is simply machine-translated rarely feels right to readers, and it usually misses how people actually search. This guide covers the main differences between Japanese and English SEO, so you can plan a Japanese version of your site properly.

Four writing systems, one search box

Japanese text combines several scripts:

Kanji are characters of Chinese origin that carry meaning.
Hiragana is a phonetic script used for grammar and native words.
Katakana is a phonetic script used mostly for foreign words, names and emphasis.
Latin letters appear in brand names, abbreviations and some searches.

The same concept can appear in more than one form. A product might be written in kanji, in hiragana for a softer tone, or in katakana as a loanword. Searchers may use any of them, and search engines are good at understanding the equivalents, but your page still needs the form most readers use for the main text, with the others where natural. Japanese text also has no spaces between words, which means search engines segment the text themselves. Write clear, natural sentences and avoid stuffing, because the algorithms read meaning and not just strings.

Keyword research in Japanese

Do not translate your English keyword list word for word. Start from how Japanese users describe the problem:

Collect queries from a native speaker who knows the topic, not only from a dictionary.
Use the autocomplete suggestions, related searches and “people also ask” boxes in Japanese search results.
Study the pages that rank, including the titles, the headings and the questions they answer.
Note which loanwords are common in katakana and which native terms people prefer.
Check search volume with a keyword tool that supports Japanese, and compare variants in different scripts.

Our guide to multilingual keyword research explains the process in more detail, and transliteration and SEO covers searches typed in two scripts. A short written brief helps the translator or writer understand why a phrase was chosen. See SEO briefs for translators.

Tone, politeness and trust

Japanese has levels of politeness. Business websites normally use a polite, respectful register, while friendly consumer brands may use a lighter one. Choose a style guide before translation starts, and apply it to headings, buttons, forms, error messages and emails. A mixture of formal and casual tone feels careless.

Trust signals carry extra weight. Readers look for company details, a physical address or a clear service area, a phone number, representative names where relevant, privacy information, return policies and clear pricing. Include them on the Japanese pages themselves and not only on the English site. Reviews, certifications and recognized partners also help. For wider ideas, read local trust signals for country versions.

Language codes, URLs and hreflang

Use clear, consistent signals for the Japanese version:

Set the HTML language attribute to ja on Japanese pages. See the HTML lang attribute.
Use hreflang with ja for Japanese content, or ja-JP if you also have other regional versions of Japanese, which is rare. Add return links on both sides. See hreflang language and region codes.
Choose a structure: a subfolder such as /ja/, a subdomain or a country domain. A subfolder is often the simplest to manage. See ccTLD, subdomain or subfolder.
Decide how to write slugs. Japanese characters in URLs are allowed and appear in readable form in many browsers, though they are encoded when copied. Romanized slugs are shorter to share. Pick one rule and keep it. See should you translate URL slugs.

Make sure no automatic redirect sends visitors or crawlers to a language based on their location, because that can hide the Japanese pages. Our guide to automatic language redirects explains why.

Encoding, fonts and page speed

Japanese text needs UTF-8 throughout: in the HTTP header, in the HTML, in the database and in feeds. Older encodings still exist on some Japanese systems, and a mismatch produces garbled text. See character encoding and SEO.

Fonts are the other practical issue. A Japanese web font contains thousands of characters and can be large. Prefer system fonts where the design allows it, or use subsetting and font loading settings so text appears without delay. Check the layout with real Japanese text, because line breaks, line height and punctuation behave differently from English. Our guide on web fonts and page speed explains how to load fonts without hurting performance.

Formats, currency and local details

Localize the details readers see every day:

Dates are commonly written with the year first, followed by month and day, with characters marking each part.
Currency is the yen, normally shown without decimals. Show tax information clearly as local customers expect.
Names and addresses follow a different order. Forms should not force a Western pattern, and should allow furigana readings where useful.
Units and sizes follow local standards, for example clothing sizes.
Payment and delivery options should match local habits, including convenience store payment or local delivery services where relevant to your business.

The article on localizing dates, numbers and units and the guide to local currency and prices list the checks to run.

Search engines, channels and content ideas

Google is the main search engine in Japan, but Japanese users also use other channels: Yahoo! Japan as a portal, Bing, social platforms, messaging apps and marketplaces. Check which channels matter in your sector, and avoid assuming that the English plan transfers. Our overview of search engines beyond Google helps with the choice.

Content that tends to work well is detailed, well structured and careful. Readers often compare options, read specifications and look for answers to practical questions before they decide. Useful formats include clear guides, comparison tables, FAQ sections, step-by-step instructions with images and pages that explain policies in plain language. Use headings that mirror the questions people ask, and place a short answer near the top.

Machine translation and quality control

Machine translation can produce a first draft quickly, but Japanese is a language where tone, context and word choice matter greatly. Have a native speaker review at least the pages that bring revenue: the home page, product or service pages, pricing, checkout and contact pages. Check titles and descriptions for length, because Japanese characters take more space than Latin letters in search results, and the display can cut text earlier than you expect. See translating title tags and meta descriptions and what is safe to publish with machine translation.

Also make sure every translated page links to other Japanese pages, not back to English ones. Navigation, footers, breadcrumbs and internal links should all stay in the chosen language. See internal linking on multilingual sites.

Common mistakes to avoid. Several errors appear again and again on Japanese versions of international sites. Pages are translated but the menu and buttons stay in English. Titles are cut off in search results because the translator counted characters like Latin letters. Product names are translated when the market knows them by their original brand. Contact forms demand a postal code format or name order from another country. Images contain text that was never translated. Each of these makes the site feel unfinished, and each is easy to catch with a page-by-page review before launch. Ask a native colleague or customer to complete a real task on the site, such as finding a price or sending a message, and note every moment of hesitation.

A launch checklist for the Japanese version

Keyword research done with native input, and pages mapped to queries.
Style guide for tone, names, terms and brand spelling.
UTF-8 everywhere, lang="ja" on pages, tested fonts.
Hreflang with return links, canonical tags to the page’s own URL and a Japanese XML sitemap or entries.
Localized formats, payment information, contact details and legal pages.
Search Console set up, and the Japanese section monitored separately.
Review of mobile layout with real text.

Site SEO AI Audit checks hreflang return links, broken language versions, x-default, language attributes, titles, descriptions and structured data on every page it crawls, and ranks the fixes by impact. The first audit of up to 200 pages is free.

The bottom line

Success in Japanese search comes from respect for the language and the reader: real keyword research, a suitable tone, clean technical signals and local details that make the site feel native. Plan the project as a market launch with native review and not as a translation task, and measure the Japanese section on its own.

KKK

Do I need a native speaker for Japanese SEO?

Yes, at least for keyword research and review. Tone, script choice and natural phrasing are hard to judge without one.

Should I use hreflang ja or ja-JP?

Language alone, ja, is normally enough. Use ja-JP only if you have a reason to separate regional variants.

Can URLs contain Japanese characters?

They can. Many sites use romanized slugs for easier sharing, others keep Japanese text. Choose one rule and apply it consistently.

Why do Japanese pages load slowly?

Large web fonts are a common cause. Use system fonts, subset the fonts or optimize font loading, and test with real text.

Is machine translation acceptable?

It can be a starting point, but have a native editor check important pages for tone, accuracy and search wording before publishing.