八よう日か

四よっ日かN5
八日 (ようか) and 四日 (よっか) are both irregular native-Japanese readings for day counters, so learners often mix up which kanji goes with which sound.
六むい日かN5
八日 (ようか) and 六日 (むいか) look similar as single-kanji day expressions but have unrelated readings that must be memorized separately.
二十日はつかN5
八日 (ようか) and 二十日 (はつか) are both special native-Japanese day readings that don't follow the regular Sino-Japanese counting pattern, so beginners often confuse them.
八やっつN5
八日 (ようか) refers to 'the 8th day of the month', whereas 八つ (やっつ) is the number eight itself used to count objects or age.

Written forms

八よう日か
Standard kanji spelling, preferred in vertical writing and formal documents.
８よう日か
Common in horizontal writing, schedules, and digital contexts.

Compound of 八 (ya, 'eight') and 日 (ka, 'day'), with a regular sound shift from yaka to yōka.