Nihon-shiki or Nippon-shiki (Japanese: 日本式, "Japan-style"; romanized as Nihon-siki or Nippon-siki in Nippon-shiki itself) is a romanization system for transcribing the Japanese language into the Roman alphabet. Among the major romanization systems for Japanese, Nippon-shiki is the most regular, and has a one-to-one relation to the kana writing systems.

It was invented by physicist Aikitsu Tanakadate (田中館 愛橘 Tanakadate Aikitsu) in 1885, and postdates the Hepburn system of romanization. Tanakadate's intention was to completely replace the traditional kanji and kana system of writing Japanese with a romanized system, which he felt would make it easier for Japanese people to compete with Western countries. Since the system was intended for Japanese people to use to write their own language, it is much more regular than Hepburn romanization, and, unlike Hepburn's system, it makes no effort to make itself easier to pronounce for English speakers.

Nippon-shiki was followed by another, similar system, Kunrei-shiki. The difference between Nippon-shiki and Kunrei-shiki is the difference between the kana syllabary and modern pronunciation. In modern standard Japanese, the sounds of the pairs di/zi ぢ/じ, du/zu づ/ず, dya/zya ぢゃ/じゃ, dyu/zyu ぢゅ/じゅ, dyo/zyo ぢょ/じょ, wi/i ゐ/い, we/e ゑ/え, kwa/ka くゎ/か, gwa/ga ぐゎ/が have become identical. For example, the word kanadukai (Nippon-shiki) かなづかい is pronounced as kanazukai in modern Japanese.

Nippon-shiki is considered the most regular of the romanization systems for the Japanese language, because it maintains a strict "one kana, two letters" form. Because it has unique forms corresponding to each of the respective pairs of kana homophones listed above, it is the only system of romanization that allows lossless mapping (so-called "round trip" mapping) to and from kana (see the hiragana article for more details).

However, because it does not follow familiar patterns of English spelling, many native speakers of English find its spelling counterintuitive. For example, the name of a type of deer, the "sika", originating from Japan, and spelt in English using Nihon-shiki, would seem to most English speakers to be pronounced as "seek-uh", rather than "she-kah". This divergence from the Japanese pronunciation is clearly caused by the romanization system. This kind of problem leads some to feel the system is not satisfactory.

Nippon-shiki has been established by the International Organization for Standardization in the ISO 3602 strict form. The JSL system, which is intended for use instructing foreign students of Japanese, is also based on Nippon-shiki.

Nipponsiki — ISO 3602 Strict

• Those in red are outdated in the language itself.
• When he へ is used as a particle it is written he not e (Kunrei-shiki/Hepburn).
• When ha は is used as a particle it is written ha not wa.
• When wo を is used as a particle it is written wo not o.
• Long vowels are indicated by a circumflex, for example long o is written ô, unlike Hepburn, which uses a macron.
• Syllabic n ん is written as n before consonants but as n' before vowels and y.
• Geminate consonants are marked by doubling the consonant following the sokuon, っ, without exception.

References

• Nihongo Daihakubutsukan (日本語大博物館), author: Jun'ichirō Kida (紀田順一郎), publisher: Just System (ジャストシステム, Jasuto Shisutem) ISBN 4883090469 (in Japanese), chapter 6.

Romanization of Japanese

Nihon-shiki | Nippon-System | Nihon-shiki | Nippon-shiki