SHI / yo / yo(tsu) / yot(tsu) / yon
four
JLPT Level 4
Jouyou Kanji, Kyouiku Grade 1
As seen in:
shigatsu - April
yokka - the fourth day of the month
yottsu - four (things)
yonin (yo'nin) - four people
Not to be confused with:
SAI / nishi - west