1.
eight days
A duration of eight days.
八日 uses native Japanese counting and means both "eight days" (duration) and "the 8th" (date).
USAGE:
- Duration: 八日かかる (takes eight days)
- Date: 八日に届く (arrives on the 8th)
- 八日間: eight-day period (adds 〜間 for explicit duration)
DAYS 1-10 (SPECIAL READINGS):
NOTE:
Days 11-31 use regular 十一日 pattern, except 二十日. The reading ようか applies only to 8, not 18 (十八日) or 28 (二十八日).