Japanese Morse Code Guide (Wabun)

Wabun Code (和文モールス符号) is the Japanese version of Morse code. Rather than translating the 26 letters of the English alphabet, Wabun assigns Morse combinations to the syllables of the Japanese kana (hiragana and katakana) syllabary.

Origins in Japanese Telegraphy

During the Meiji Restoration, Japan underwent rapid modernization, including the adoption of the electric telegraph. However, the Western International Morse standard, designed around the Latin alphabet, was completely unsuited for the Japanese writing system. Rather than forcing telegraph operators to transliterate Japanese into Roman characters (romaji), Japanese engineers developed a custom spelling code. Finalized in the late 19th century, Wabun code mapped Morse signals directly to the 48 core sounds of the traditional iroha kana ordering, allowing instant, native telegraph communication across the Japanese archipelago.

How it Works: Kana-to-Wabun Mappings

Because the Japanese language consists of many more foundational phonetic sounds than there are letters in the English alphabet, Wabun requires a much broader library of patterns. Many characters utilize 4-character and 5-character combinations to ensure all syllables have unique codes. The mappings are completely independent of the English standard. For example, while the English letter "A" is `.-`, in Wabun, `.-` represents the Kana character "イ" (i). The sound "ハ" (ha) is represented by `-...`, which corresponds to the letter "B" in the West. This means a direct, character-by-character Morse decode of a Wabun transmission using Western rules yields complete gibberish, highlighting the necessity of contextual indicators.

The DO and SN Prosigns in Real Radio Contacts

In global maritime and amateur radio networks, operators regularly communicate across borders. To prevent confusion when shifting between languages, standard procedural signals (prosigns) are used. When a Japanese operator wants to transmit a message in native Japanese Kana, they send the prosign **DO** (.-.---, run together as a single character) to alert the receiver that Wabun rules now apply. Once the Japanese message is complete and the operator wishes to return to standard English/International Morse code, they transmit the prosign **SN** (...-., meaning "understood" or "switching back"), resetting the receiver's context.