乙 Radical 5 — the second of the ten heavenly stems; a bent, hooked stroke
yǐ (third tone, dipping)
the second of the ten heavenly stems; a bent, hooked stroke
Radical 51 stroke2 characters
Also written 乚 · 乛 — the same radical in a different position inside the character.
Where the shape comes from
One curving stroke. The Shuowen reads the curve as a shoot doubling over as it forces its way up through ground still cold, and the graph was borrowed early for the second heavenly stem — the "B" of the traditional ordering, still used to label a second item. As a heading it takes characters whose skeleton is a hook: 九, 也, 书, 乱.