五つ
いつつ · itsutsu · JLPT N5 · noun
five (things)
🖐️ 五つ = itsu (five) + tsu (native counter): five things
Native Japanese counting adds つ to the old number root: hitotsu, futatsu, mittsu, yottsu, itsutsu. The root itsu- also appears in 五日 (itsuka, the 5th day). Sound hook: it's-two-tsu, yet it means five.
五 — two horizontal lines + crossed strokes
五 originally depicted two parallel lines (heaven and earth) with an X between them, representing the interaction of the five elements. Over time it became the standard numeral for 'five.' The ancient form 㐅 (just the X) was later framed by the two lines to distinguish it clearly as a number.