Rendaku (連濁, Japanese pronunciation: [ɾendakɯ], lit. "sequential voicing") is a phenomenon in Japanese morphophonology that governs the voicing of the initial consonant of a non-initial portion of a compound or prefixed word. In modern Japanese, rendaku is common but at times unpredictable, with certain words unaffected by it.

While kanji do not indicate rendaku, they are marked in kana with dakuten (voicing mark).


Consonants (in Hepburn) undergoing rendaku [1]
Unvoiced Voiced
k g
s, sh z, j
t, ch, ts d, j, z
h, f b

Rendaku can be seen in the following words:

ひと + ひと → ひと-びと (人々) ( iteration)
hito + hitohitobito ("person" + "person" → "people")
いけ + はな → いけばな
ike + hanaikebana ("keep alive" + "flower" → "flower arrangement")
とき + とき → とき-どき
toki + tokitokidoki ("time" + "time" → "sometimes")
て + かみ → て-がみ
te + kamitegami ("hand" + "paper" → "letter")
おり + かみ → おり-がみ
ori + kamiorigami ("fold" + "paper" → "paperfolding")
はな + ひ → はな-び
hana + hi → hanabi ("flower" + "fire" → "firework")
はな + ち → はな-ぢ
hana + chihanaji ("nose" + "blood" → "nosebleed")
まき + すし → まき-ずし
maki + sushimakizushi ("roll" + "sushi" → " nori-wrapped sushi") ( Rendaku is prevalent with words that end in sushi.)
やま + てら → やま-でら
yama + teraYama-dera ("mountain" + "temple")
こころ + つかい → こころ-づかい
kokoro + tsukaikokorozukai ("heart" + "using" → "consideration" or "thoughtfulness")
おぼろ + つき → おぼろ-づき
oboro + tsukioborozuki ("haze" + "moon" → "hazy moon")
ふじ + はら → ふじわら
fuji + haraFujiwara ("wisteria" + "field" → "Fujiwara")

In some cases, rendaku varies depending on syntax. For instance, the suffix tōri (〜通り, "road, following"), from tōru (通る, "to go, to follow"), is pronounced as -tōri (〜とおり) following the perfective verb, as in omotta-tōri (思った通り, "as I thought"), but is pronounced as -dōri (〜どおり, with rendaku) when following a noun, as in yotei-dōri (予定通り, "as planned, according to schedule") or, semantically differently – more concretely – Muromachi-dōri (室町通, "Muromachi Street").

Rendaku occurs not only on single-root elements, but also "multi-root" elements, those that are themselves composed of smaller elements. These morphemes may also be of Chinese origin (see kango) or even of non-Literary-Chinese origin (see gairaigo) rather than strictly native.

けん + しゃ → けん-じゃ
ken + shakenja ("wise" + "-er" → "wiseman; philosopher")
Here, kenja is a kango.
ちゅう + こく → ちゅう-ごく
chū + kokuChūgoku ("center" + "country; -land" → "China; Chūgoku")
Here, Chūgoku is also a kango.
ひら + か-な → ひら-が-な
hira + kanahiragana ("plain" + "character", compare かた-か-な katakana, which does not undergo rendaku)
きゃく + ふ-とん → きゃく-ぶ-とん
kyaku + futonkyakubuton ("guest" + "bedding" → "bedding for guests")
Here, futon is a Chinese borrowing
ろ-てん + ふ-ろ → ろ-てん-ぶ-ろ
roten + furorotenburo ("outdoor" + "bath" → "outdoor bath")
ゆめ-み + ここ-ち → ゆめ-み-ごこ-ち
yumemi + kokochiyumemigokochi ("dreaming" + "state of mind" → "dream state")
おぼろ + つき-よ → おぼろ-づき-よ
oboro + tsukiyooborozukiyo ("haze" + "moonlit night" → "hazy moonlit night")
Here, tsukiyo is a compound word, composed of tsuki ("moon") and yo ("night")
いろ + ちゃ-や → いろ-ぢゃ-や
iro + chayairojaya ("lust" + "teahouse" → "brothel teahouse")
Here, chaya is a compound word, composed of cha ("tea") and ya ("shop"); cha by itself generally doesn't undergo rendaku, but chaya frequently does
ぼん + ちょう-ちん → ぼん-ぢょう-ちん
Bon + chōchinBonjōchin (" Bon" + "lantern" → "Bon lantern")
Here, chōchin is a Chinese borrowing, composed of chō ("portable") and chin ("lamp")
おや + かい-しゃ → おや-がい-しゃ
oya + kaishaoyagaisha ("parent" + "company" → "parent company")
Here, kaisha is a kango, composed of kai ("gathering") and sha ("company")
かぶしき + かいしゃ → かぶしきがいしゃ
kabushiki + kaishakabushikigaisha ("stock-type" + "company" → "joint-stock company")
あめ + カッパ → あま-ガッパ
ame + kappaamagappa ("rain" + "raincoat" → "raincoat")
Here, kappa is a gairaigo, from the Portuguese word capa ("cloak; cape")
いろは + カルタ → いろは-ガルタ
iroha + karutairohagaruta
Here, karuta is a gairaigo, from the Portuguese word carta ("card")
みず + キセル → みず-ギセル
mizu + kiserumizugiseru ("water" + "pipe" → "hooka")
Here, kiseru is a gairaigo, from the Khmer word khsiə ("pipe")

Notice that for certain morphemes that begin with the morae chi () and tsu (), their rendaku forms begin with the morae ji and zu, spelled precisely in hiragana as and , which explains the use of these kana in contrast to the identically pronounced and (see yotsugana). This isn't a hard and fast rule, however, because it's relaxed in certain older compounds or names, especially those that are so consolidated that they could hardly be recognized as compounds anymore, but rather, as single words themselves.

Rendaku occurs not only in compound nouns, but also in compounds with adjectives, verbs or continuative/nominal forms of verbs.

め + ふ-く → め-ぶ-く
me + fu-kumebu-ku ("sprout" + "to blow" → "to bud")
おとこ + きら-い → おとこ-ぎら-い
otoko + kira-iotokogira-i ("male person" + "dislike; hatred" → "dislike for men; misandry")
おんな + す-き → おんな-ず-き
onna + su-kionnazu-ki ("female person" + "liking; fondness" → "fondness for women; woman lover")
お-き + さ-り → お-き-ざ-り
o-ki + sa-rio-ki-za-ri ("putting" + "leaving" → "deserting")
くる-い + さ-き → くる-い-ざ-き
kuru-i + sa-kikuru-i-za-ki ("being in disarray" + "blooming" → "unseasonable blooming")
うす- + きたな-い → うす-ぎたな-い
usu- + kitana-iusugitana-i ("faint-; light-" + "dirty" → "dirty")
くち + きたな-い → くち-ぎたな-い
kuchi + kitana-ikuchigitana-i ("mouth" + "dirty" → "foulmouthed; scurrilous")
た-ち + とま-る → た-ち-どま-る
ta-chi + toma-ruta-chi-doma-ru ("standing; starting; igniting" + "to stop" → "to stop")

Properties blocking rendaku

Research into defining the range of situations affected by rendaku has largely been limited to finding circumstances (outlined below) which cause the phenomenon not to manifest.

Lyman's Law

Lyman's Law states that there can be no more than one voiced obstruent (a consonant sound formed by obstructing airflow) within a morpheme.[2] Therefore, no rendaku can occur if the second element contains a voiced obstruent. This is considered to be one of the most fundamental of the rules governing rendaku.

yama + kado > Yamakado, not * Yamagado ("mountain" + "gate" > place name) (* indicates a non-existent form)
hitori + tabi > hitoritabi, not * hitoridabi ("one person" + "travel" > "traveling alone")
yama + kaji > yamakaji, not * yamagaji ("mountain" + "fire" > "mountain fire")
tsuno + tokage > tsunotokage, not * tsunodokage ("horn" + "lizard" > "horned lizard")

Although this law is named after Benjamin Smith Lyman, who independently propounded it in 1894, it is really a re-discovery. The Edo period linguists Kamo no Mabuchi[3][4] (1765) and Motoori Norinaga[5][6] (1767–1798) separately and independently identified the law during the 18th century.

Lexical properties

Similar to Lyman's Law, it has been found that for some lexical items, rendaku does not manifest if there is a voiced obstruent near the morphemic boundary, including preceding the boundary.

Some lexical items tend to resist rendaku voicing regardless of other conditions, while some tend to accept it.

Rendaku usually only applies to native Japanese words, but it also occurs infrequently in Sino-Japanese words (Japanese words of Chinese origin) especially where the element undergoing rendaku is well integrated ("vulgarized").

kabushiki + kaisha > kabushiki-gaisha ("stock" + "company" > "corporation")
ao + shashin > aojashin ("blue" + "photo" > "blueprint")

It is even rarer to find rendaku among words of foreign origin, unless the loanword has become completely absorbed into Japanese:

ama + kappa > amagappa ("rain" + "coat" [a Portuguese loan, capa] > "raincoat").
aisu + kōhī > aisukōhī, not * aisugōhī ("ice" + "coffee" > "iced coffee")


Rendaku also tends not to manifest in compounds which have the semantic value of "X and Y" (so-called dvandva or copulative compounds):

yama + kawa > yamakawa "mountains and rivers"

Compare this to yama + kawa > yamagawa "mountain river".

Branching constraint

Rendaku is also blocked by what is called a "branching constraint".[7] In a right-branching compound, the process is blocked in the left-branching elements:

mon + ( shiro + chō) > monshirochō, not * monjirochō (" family crest" + {"white" + "butterfly"} > " cabbage butterfly")


( o + shiro) + washi > ojirowashi ({"tail" + "white"} + "eagle" > " white-tailed eagle")

Further considerations

Despite a number of rules which have been formulated to help explain the distribution of the effect of rendaku, there still remain many examples of words in which rendaku manifests in ways currently unpredictable. Some instances are linked with a lexical property as noted above but others may obey laws yet to be discovered. Rendaku thus remains partially unpredictable, sometimes presenting a problem even to native speakers[citation needed], particularly in Japanese names, where rendaku occurs or fails to occur often without obvious cause. In many cases, an identically written name may either have or not have rendaku, depending on the person. For example, 中田 may be read in a number of ways, including both Nakata and Nakada.

Voicing of preceding consonant

In some cases, voicing of preceding consonants also occurs, as in sazanami (細波, ripple), which was formerly sasa-nami. This is rare and irregular, however.

See also