id = candidate ID
name = name (recorded in Japanese)
prefid = prefecture code (1-47)
pref = name of the prefecture
distnum = district id within the prefecture
party
   1--LDP
   2--DPJ
   3--New Komeito
   4--JCP
   5--SDP
  20--Kokumin Shinto (People's New Party)
  21--Shinto Nippon (New Party Nippon)
  22--Shinto Daichi (New Party Daichi)
  98--others
  99--independents

dual = also ran in PR (1) or not (0)
win = 0 lost; 1 lost in the SMD but won in PR; 2 won in the SMD
inc = incumbent (1) or not (0)

votes = number of votes received
voter = number of eligible voters on the election day.

Sources: 
<http://www.sankei.co.jp>, accessed on September 12, 2005.
<http://topics.kyodo.co.jp/05election/result/k_senkyoku.html>, accessed on Feb 2, 2007.