Reading 九十九 as "tsukumo"


Why can 九十九 be read as "tsukumo"? I don't understand how those kanji could be
read that way.




I looked up in my etymology dictionary (小学館's 日本語源大辞典) :)

The answer goes like this:

  1. つくも was originally a name of a kind of plant (modern standard name: フトイ; English name is _softstem bulrush_ or _great bulrush_ according to Wikipedia).
  2. A compound word つくもがみ < つくも + かみ "disheveled white hair (especially of old women)" was coined, because of its resemblance to the plant. This word is seen in 伊勢物語 from the 10th century.
  3. The kanji 九十九髪 came with the word. This kanji was actually kind of a word-played ateji intending to mean "white hair". Its logic was like a riddle and went like this: **white = 白 = ( 百 without 一 ) = 100 - 1 = 99 = 九十九**. 
  4. Afterwards [九十九]{つくも} became to be used without 髪 in some other words (mainly proper nouns), like 九十九湾 "Tsukumo Bay" in Ishikawa pref., or several rare family names like 九十九, [九十九里]{つくもり}.

So, how amusing. In modern Japanese, [白寿]{はくじゅ} means "the celebration of 99th
birthday", and it must be under the same logic (in the reverse way). But few
people know why 九十九 reads つくも, I guess.




I looked up in my etymology dictionary (小学館's 日本語源大辞典) :)

The answer goes like this:

  1. つくも was originally a name of a kind of plant (modern standard name: フトイ; English name is _softstem bulrush_ or _great bulrush_ according to Wikipedia).
  2. A compound word つくもがみ < つくも + かみ "disheveled white hair (especially of old women)" was coined, because of its resemblance to the plant. This word is seen in 伊勢物語 from the 10th century.
  3. The kanji 九十九髪 came with the word. This kanji was actually kind of a word-played ateji intending to mean "white hair". Its logic was like a riddle and went like this: **white = 白 = ( 百 without 一 ) = 100 - 1 = 99 = 九十九**. 
  4. Afterwards [九十九]{つくも} became to be used without 髪 in some other words (mainly proper nouns), like 九十九湾 "Tsukumo Bay" in Ishikawa pref., or several rare family names like 九十九, [九十九里]{つくもり}.

So, how amusing. In modern Japanese, [白寿]{はくじゅ} means "the celebration of 99th
birthday", and it must be under the same logic (in the reverse way). But few
people know why 九十九 reads つくも, I guess.

