Japanese Braille

Japanese Braille is the braille script of the Japanese language. It is based on the original braille script, though the connection is tenuous. In Japanese it is known as , literally "dot characters". It transcribes Japanese more or less as it would be written in the "hiragana" or "katakana" syllabaries, without any provision for writing "kanji".
Japanese Braille is a vowel-based abugida. That is, the glyphs are syllabic, but unlike kana they contain separate symbols for consonant and vowel, and the vowel takes primacy. The vowels are written in the upper left corner (points 1, 2, 4) and may be used alone. The consonants are written in the lower right corner (points 3, 5, 6) and cannot occur alone. However, the semivowel "y" is indicated by point 4, one of the vowel points, and the vowel combination is dropped to the bottom of the block. When this point is written in isolation, it indicates that the following syllable has a medial "y", as in "mya". Syllables beginning with "w" are indicated by dropping the vowel points to the bottom of the cell without additional consonant points.
Main chart.
The chart below shows each braille character under the corresponding "hiragana" and its romanization. In order to illustrate the derivation of each character from its component vowel and consonant, the vowel points are written in black, and the consonant points in green. There is no such distinction in braille as it is actually used.
The vowels are assigned the braille patterns that occupy the upper-left half of the cell (dots 1-2-4) in numerical order: . (These are the first five letters of Braille's alphabet, , rotated to fit the available space.) The consonantal diacritics, on the other hand, have no apparent connection to international values or numerical order, corresponding as they do to international punctuation and formatting marks.
Other symbols.
In kana, a small "tsu" (), called "sokuon", is used to indicate that the following consonant is geminate, and in interjections as a glottal stop. In katakana only, a long vowel is indicated with a horizontal stroke () called a chōon. This also looks like a half dash in braille:
The placement of these blocks mirrors the equivalent kana: the "sokuon" indicates that the following consonant is geminate, whereas the "chōon" indicates that the preceding vowel is long.
In kana, the voiced consonants "g, z, d, b" are derived from the voiceless consonants "k, s, t, h" by adding a diacritic called "dakuten" to the kana, as in "gi"; in foreign words, "vu" is written by adding this to the vowel "u". Similarly, "p" is derived from "h" by adding a small circle, "handakuten". Two kana are fused into a single syllable by writing the second small, as in "kya" from "ki + ya"; this is called "yōon".
In Japanese Braille, the signs for these are prefixes. That is, the order is "dakuten" + "ki" for "gi". When more than one occurs in a single syllable, they are combined in a single prefix block, as the "yōon-dakuten" used for "gya".
The "yōon" prefix uses the point that represents "y" in the blocks "ya", "yu", "yo". When placed before "ka", "ku", "ko", it produces "kya", "kyu", "kyo". Likewise, the "yōon-dakuten" prefix before "ka, ku, ko" creates "gya, gyu, gyo." And so on for the other consonants.
Unlike kana, which uses a subscript "e", in braille the "-ye" in foreign borrowings is written with "yōon" and the kana from the "e" row: that is, "kye", "she", "che", "nye", "hye", "mye", "rye", voiced "gye", "je", "bye", and plosive "pye" are written with the "yōon" prefixes plus "ke", "se", "te", "ne", "he", "me", "re". The syllable "ye" is written "yōon" plus "e."
There is also a prefix for medial "-w-" called "gōyōon". When combined with "ka", it produces the obsolete syllable "kwa". It may also be fused with the voicing prefix for "gwa". For foreign borrowings, this extends to "kwi", "kwe", "kwo" and "gwa", "gwi", "gwe", "gwo". "Gōyōon" may also be combined with the vowels "i", "e", "o" for foreign "wi", "we", "wo" (now that the "w" in the original Japanese kana for "wi", "we", "wo" is silent); with "ha", "hi", "he", "ho" for "fa", "fi", "fe", "fo" and (when voiced) for "va", "vi", "ve", "vo"; and with "ta", "chi", "te", "to" for "tsa", "tsi", "tse", "tso". These two prefixes are identical to the question mark and full stop.
These all parallel usage in kana. However, there are additional conventions which are unique to braille. "Yōon" and "yōon-dakuten" are also added to "chi" and "shi" to write "ti", "di" and "si", "zi" found in foreign borrowings; similarly "gōyōon" and "gōyōon-dakuten" are added to "tsu" to write "tu", "du". This differs from the system used in kana, where the base syllables are "te" and "to" respectively, and a subscript vowel "i" or "u" is added.
In an assignment that is counter-intuitive in kana, "yōon + handakuten" is prefixed to "tsu", "yu", "yo" to produce "tyu", "fyu", "fyo" in foreign words, and voiced for "dyu", "vyu", "vyo". The latter—"yōon + dakuten + handakuten", is impossible in kana:
Orthography.
Japanese Braille is written as print Japanese would be written in kana. However, there are three discrepancies:
Punctuation.
Besides the punctuation of Japanese, braille also has symbols to indicate that the following characters are digits or the Latin alphabet.
As noted above, the space is used between words and also where an interpunct would be used when names are written in katakana. There are several additional punctuation marks.
Formatting.
Western letters and digits are indicated as follows:
An additional sign indicates that the following characters are specifically English words and not just in the Latin alphabet.
Words immediately follow numbers, unless they begin with a vowel or with "r-". Because the syllables "a i u e o" and "ra ri ru re ro" are homographic with the digits 0–9, a hyphen is inserted to separate them. Thus "six people" ("6 nin") is written without a hyphen, , but "six yen" ("6 en") is written with a hyphen, , because would be read as .
Kanji.
An eight-dot extension of Japanese Braille, "kantenji", has been devised to transcribe kanji.