Japanese IME Not Working? Fix It Symptom by Symptom

Japanese input fails in a small number of very specific ways, and almost all of them are one setting in the wrong position. This page is organised by symptom, so you can skim to the one that matches your screen. If you have not installed the Japanese keyboard yet, that is a different job — start with Japanese keyboard setup, then come back here if it still misbehaves.

Symptom index

The 30-second check before anything else

Look at the mode indicator. Every IME shows one, and it is the single most useful status display on your machine.

It sits in the Windows taskbar near the clock, in the macOS menu bar at the top right, and in the keyboard row on phones. If it says A, nothing is broken — you are in the wrong mode.

Then try the operating system's own language switch rather than the IME's hotkey. On Windows that is usually Windows key + Space, which bypasses any app that has captured the IME's shortcut. If the OS switch works and the IME hotkey does not, you have a shortcut conflict: that is Fix 6.

1. You keep getting plain English letters

Symptom. The Japanese keyboard is installed and selected, but typing produces konnichiwa on screen instead of こんにちは (konnichiwa, hello).

Cause. Direct input mode — often written as A mode, or 英数 (eisu, alphanumeric). It is the IME being on but idle. Japanese input methods deliberately start here so that you can type a URL or a password without fighting them.

Fix. Switch the mode, not the language. Press the IME's toggle key once and confirm the indicator changes from A to あ.

• Windows. The 半角/全角 (hankaku/zenkaku) key on a Japanese keyboard, or Alt + backtick (top left, under Esc) on a US keyboard. Press Alt bare — Shift plus that key types the tilde. Microsoft IME lets you rebind this, in a key-settings page whose name varies by Windows version.
• macOS. No single toggle. You select an input source and it remembers its last mode, so if it arrives in A, use the input menu to pick the hiragana entry.
• Phone. Tap the あ key on the keyboard itself.

If the indicator will not change at all, you are not in the IME — that is Fix 4.

2. You get full-width letters instead of kana

Symptom. You type this and get ｔｈｉｓ — characters that look like ordinary letters but are wider, evenly spaced, and match nothing in a search box or a login form.

Cause. Japanese text has two widths. Full-width characters 全角 (zenkaku, full-width) occupy a kanji-sized square; half-width characters 半角 (hankaku, half-width) are the Latin letters you are used to. The IME can be set to produce full-width Latin, and this is a real problem rather than a cosmetic one: a full-width ｔ is a different character from a normal t, so nothing will find it and a form may reject it.

Fix. Press the 半角/全角 key if your keyboard has one. On a US keyboard, that function usually lives on the same Alt + backtick combination that toggles IME mode, so pressing it twice gets you back to kana mode. On a phone it is a key in the keyboard row.

If you have already typed the text, do not retype it. Most IMEs convert the text you are still composing when you press a function key: the F6 to F10 range cycles a highlighted string through hiragana, katakana, and full-width and half-width alphanumeric forms. The assignments differ between IMEs, so check your IME's own help if a key does nothing; the half-width alphanumeric one is what flattens ｔｈｉｓ back into this.

How to tell this apart from Fix 1. Wide letters mean the IME is running and converting, just into the wrong character class. Ordinary narrow English means it is not converting at all.

3. Japanese is not in the keyboard list at all

Symptom. There is no Japanese entry to select. The list only has your own language.

Cause. The Japanese language was never added. This surprises people because Japanese fonts are often already present, so Japanese pages look fine — but rendering Japanese and typing Japanese are separate capabilities.

Fix. Add the language, including its language pack where you are offered one.

Menu names move between OS versions, so follow the labels rather than looking for one exact string.

There is a sneakier Windows variant: the language is installed but no keyboard is attached to it. On Windows a language and its keyboard layouts are separate lists, and a language with no keyboard looks installed but cannot be selected. That is Fix 4.

4. Installed but you cannot switch into it

Symptom. Japanese is in your language list, but the switch shortcut cycles past it or does nothing at all.

Cause. Usually one of three things: the shortcut is taken by another program; the language has no keyboard attached; or you are pressing the wrong shortcut for your operating system.

All of these are reassignable, and the menus that reassign them differ between OS versions. If a shortcut does nothing, assume the binding is wrong rather than the IME, and look for an input-source or text-input heading in your keyboard shortcut settings.

Then check the list itself. In Windows, expand the Japanese entry in your language settings and confirm a keyboard is listed inside it; if the list is empty, add one. Adding a language does not always add its keyboard.

Successfully switching to Japanese and still seeing English letters is Fix 1, not this one.

5. Everything renders as empty boxes

Symptom. Your own typed text looks fine, but pasted Japanese, a Japanese web page, or an app's menu shows rows of empty rectangles.

Cause. Missing Japanese fonts. Those rectangles are the glyph a font shows when it has no character for a codepoint. In Japanese typography they are nicknamed 豆腐 (toufu, tofu), from the resemblance to a block of it.

Fix. Install a font that covers Japanese. Noto Sans JP, Source Han Sans, Yu Gothic, Meiryo, IPAex Gothic and Hiragino Sans all work; you do not need a specific one. On Windows, Japanese fonts ship as an optional language feature you add through the language settings. On macOS, Hiragino ships with the system, so tofu there usually means an app is specifying a font that lacks Japanese coverage rather than the system missing one. On Android and Linux, install Noto Sans CJK JP or the equivalent package, under a name that varies by vendor and distribution.

Tofu is sometimes confused with mojibake. They are different problems. Tofu means the character is known but unrenderable. 文字化け (mojibake, garbled text) means the bytes were decoded with the wrong encoding and produced the wrong characters entirely — a text-encoding problem in the file or the app, which installing fonts will not fix.

6. It works everywhere except one app

Symptom. Fine in your browser and your notes app. In one specific program — usually a game, a full-screen app, a remote desktop session or a virtual machine — the shortcut does nothing.

Cause. That program is capturing the keystroke before the IME sees it. Full-screen games commonly grab the whole keyboard. Remote desktop and virtual machine clients forward keys to a remote machine that may have no IME of its own. And plenty of ordinary apps bind Alt or Control combinations for their own features.

Fix.

1. Use the OS-level switch instead of the IME hotkey. Windows key + Space, or the macOS input menu. The operating system handles these, so apps cannot intercept them — this alone fixes most cases.
2. Leave full-screen exclusive mode. Run the app windowed or borderless. Exclusive full-screen keyboard capture is the most common single cause.
3. Check the app's own shortcut settings and rebind whichever of the two collisions you can live without.
4. For remote desktop and virtual machines, install the IME on the remote machine. A remote session sends keystrokes, not characters, so a Japanese IME running locally will not help.
5. Try Notepad or TextEdit as a control. Working there but not in the target app means the app is at fault and the operating system is not, which narrows the search considerably.

7. n or small っ gives the wrong kana

Symptom. shinichi gives しにち instead of しんいち (Shin'ichi, a name). kite gives きて (kite, to come) instead of きって (kitte, stamp). koreha gives これは (kore wa, this is).

Cause. None of these are bugs. They are the input rules working exactly as designed. A single n before a vowel or a y starts a new syllable, so ん (n) needs nn — which is never wrong. Small っ is written by doubling the next consonant. And ha produces は, because you type the kana's own romaji even when the particle is read "wa".

That last point needs a distinction most tutorials skip: there are two romaji, one for your fingers and one for your mouth. The full treatment is in how to type in Japanese, and every exception to the plain-syllable rules is collected in romaji typing exceptions.

To check whether a sentence reads the way you think it does, paste it into the romaji converter and compare the output against what you typed. It is a fast way to separate a rule you have not learned yet from an actual setup problem.

8. It works in one window and not another

Symptom. Japanese works in one app, then you click into another and it is English again. Switch back and it works again.

Cause. Windows can be configured either to share one input method across every window, or to let each window keep its own. With the per-window setting on, changing apps changes your input mode — which looks exactly like the IME randomly dying.

Fix. Windows has an advanced keyboard setting controlling whether each app window remembers its own input method. The wording changes between versions, so look for something about using a different input method for each app window. Turn it off if you want one mode everywhere, or leave it on and accept re-pressing the toggle after switching windows.

If the pattern is not per-window but per-app — always broken in the same program, fine everywhere else — that is Fix 6 instead.

When to reset instead of debug

If you have worked through everything above and the IME is still inconsistent, restart cleanly: remove the Japanese language entirely, sign out or restart, and add it again. This clears a surprising number of stuck states, particularly on Windows, where a half-removed language can leave a broken keyboard layout behind. On macOS, remove and re-add the input source and log out and back in.

One thing a reset genuinely fixes: on Windows, adding the Japanese language can leave a JIS keyboard layout active even if your physical keyboard is a US one. The symptom is unmistakable — Shift + 2 gives you " instead of @, and @ has moved to its own key near the letter P. That is a layout mismatch, not an IME fault, and the fix is to select the US keyboard layout inside the language settings. The differences between the two layouts are covered in Japanese keyboard setup.

One useful thing to know: on Romaji.live you write the pronunciation romaji rather than driving an IME, so none of the failure modes above apply — これは (kore wa, this is) is typed on your existing keyboard as kore wa. Which makes it a decent way to keep practising on a machine where the IME is fighting you. Our interactive kana table covers the base syllabary, and practice puts whole sentences in front of you.