Most people have heard of the opposition between Traditional Chinese and the other widely used Chinese writing system, Simplified Chinese, but Japanese tends to be viewed as a monolith. This is probably because both TC and SC are widely used, but Japanese is almost always written in only one orthography—the one introduced in the postwar reforms.

Even when people have heard of the reform, it probably wouldn’t occur to them to refer to the postwar orthography as “Simplified Japanese”, even though that is exactly what it is. My use of “Traditional Japanese” mirrors that of “Traditional Chinese” to distinguish it from “Simplified Japanese”, partially for laughs, but mostly seriously.

What is Traditional Japanese?

I admit that I am, ironically, simplifying this a little bit. There are three character sets that are relevant to this discussion of Japanese writing: hiragana, katakana, and Chinese characters. Since the two former sets are interchangeable, we can consider them collectively and refer to them as kana. When I say “Traditional Japanese”, I mean both the traditional shape of the Chinese characters and the traditional kana spelling.

Traditional Characters

It is not unheard of for historical texts to now be rendered in what is often called old kana spelling or historical kana spelling, but with simplified characters. It also wasn’t unheard of historically to simplify characters here and there, but the standard shape was shared throughout the Sinosphere (roughly modern Japan, Korea, Vietnam, and Greater China), and is the shape recorded in the KangHsi Dictionary (康煕字典). Some people also use the traditional shapes of characters with the new kana orthography, but this is even less common.

Traditional characters are rather straightforward, since they correspond to the KangHsi shapes. Sometimes, though, the preferred character variants in Japan differed from those in China, and this is still the case, so you usually see 踊, 澁, 雇, 勞働, and 豫定 in Japan and 踴, 澀, 僱, 勞動, and 預定 in China. There are also some characters that were made in Japan, such as 込, 畑, and of course 働 above. In one case, four characters are collapsed into one: 辨 (and its variant 辧), 辯, 瓣, and 弁 are all written 弁 in the new orthography, but it isn’t uncommon to see it used for 辮 and 辦 as well. In addition, for some words, the character spellings were changed to variant spellings that used more common characters, such as 交叉→交差.

Traditional Kana Orthography

The traditional kana spelling is slightly more complicated. While the new kana spelling has a low number of possible spelling corresponding to phonemes (almost 1:1, but not quite), the traditional one has many ways to spell the same sound. This is because it preserves distinctions that have been lost in speech. Consider /oː/, which can be spelled ⟨おう, おお⟩ in the new orthography, but also ⟨おを, おほ, おふ, あう, あふ⟩ in the traditional one. This does make it more difficult to spell, but reading is still straightforward, because these sequences are always read /oː/, with one exception: verbs ending in /u/. A verb like ⟨會ふ⟩ ‘to meet’ would be rendered ⟨あふ⟩, but read /aꜜu/, not /oꜜː/. (Many people do read it as /oꜜː/ when reading texts in Traditional Japanese, but I consider that an erroneous reading pronunciation.)

Distinctions

The simplified kana orthography collapses these distinctions to correspond to pronunciation:

• わ行 ‘wa-line’ kana and あ行 ‘a-line’ kana: ゐ→い, ゑ→え, を→お. (The new orthography retains を only as an accusative marker.)
• Word-medial (intervocalic) は行 ‘ha-line’ and わ行 ‘wa-line’ (which is already mostly collapsed into the あ行 ‘a-line’—see above): あは→あわ, あひ→あい, あふ→あう, あへ→あえ, あほ→あお. (This only occurs within stems, and there are a few exceptions, such as あひる ‘duck’.)
• くわ→か, ぐわ→が.
• The so-called “yotsugana”: ぢ→じ, づ→ず. (The new orthography retains づ and ぢ where つ and ち are voiced in compound words in a process called 連濁 [rendaku]. In addition, 痔 ‘hæmorrhoids’ is still often written ぢ.)
• あ+う sequences and お+う sequences: あう→おう, あふ→おう. (Notice that this leads to おお and おう still being distinguished.)
• え+う sequences and よう: せう→しょう, けふ→きょう, etc.
• い+う sequences and ゆう: きう→きゅう, じふ→じゅう, etc.
• く, き, ち, つ→っ where it before か行 ‘ka-line’ and た行 ‘ta-line’ kana (and indeed anywhere つ marks a long consonant): 學校 ‘school’ ガクカウ→ガッコウ, 決定 ‘decision’ ケツテイ→ケッテイ, びつくり→びっくり etc. (Compound words are excepted from this, so e.g. 洗濯+機 ‘washing machine’ センタク+キ does not officially become センタッ+キ.)

These changes “stack”, as it were, so は行 ‘ha-line’ kana going to the わ行 ‘wa-line’ go on to the あ行 ‘a-line’ unless they become わ /wa/, and くわう also becomes こう.

New Distinctions

The new orthography did actually introduce a new distinction, namely small kana. ゃ, ゅ, ょ, っ (and ゎ) used to be written や, ゆ, よ, つ (and わ), which could cause ambiguities. However, many cases of く, き, and ち also became っ.

Etymological Kana Orthography

Because the traditional orthography makes many historical distinctions, it is often included in Japanese dictionaries (though not in Japanese—English ones), and especially character dictionaries. In fact, many of these dictionaries make more distinctions than the historical orthography in Sino-Japanese readings of characters. I call this deep historical kana orthography. Sino-Japanese readings are conventionally rendered in katakana:

• Final ン and ム. These were considered variants until the early 20th century, but are distinguished in character dictionaries to show whether a character had -n or -m, respectively, in Middle Chinese.
• Medial ヰ and ヱ, analogous to クワ. For example, 兄 was spelled キヤウ, but is often rendered クヰヤウ in “deep” orthography. (Some dictionaries also write them as small kana in these cases, but there are no Unicode characters for for small ゐ, ヰ, ゑ, or ヱ.)
• Sometimes, ウ and イ are rendered in small kana as ゥ and ィ when they derive from a Middle Chinese /ŋ/.

My Preferred Spelling

I like to use the deepest kana orthography I possibly can, including small ヰ and ヱ, when I can help it. In practice, though, “deep” kana orthography looks exactly the same as the traditional spelling, since Sino-Japanese is almost always written in Chinese characters.

Although I prefer etymological spelling, as long as it’s (mostly) read in a regular way, I don’t really hate the new spelling. I see it as an informal shortcut that would be well suited for handwritten notes scribbled down in a hurry, but less appropriate for formal texts. This is also the attitude I have towards Simplified Chinese or indeed any kind of character variants.

How to Learn Traditional Japanese

Most serious Japanese dictionaries written for Japanese readers include the traditional spelling, but not the “deep” variant. For that, you’ll need a character dictionary written for Japanese readers, such as 漢字源, or rely on Wiktionary (especially Japanese Wiktionary is good at adding these spellings).

For traditional characters, you can usually rely on lists that show the simplified Jōyō characters (常用漢字), but you have to watch out for changed character spellings and which character to use for 弁, although some serious dictionaries actually do help you with that. An example is Sanseidō’s 新明解國語辭典, which also includes traditional spellings and Standard Japanese pitch patterns.

I hope this helps. I am also working on a learner’s dictionary and textbook for Traditional Japanese, but it will take a while to finish.