auxiliary verb, ichidan verb
begin to; start to
Attaches to the continuative form (連用形) of verbs to express the beginning of an action or state. Often used in literary or formal contexts; in casual speech, 〜始める (〜はじめる) is more common.
花が咲き初める。
The flowers begin to bloom.
空が明るみ初める頃、出発した。
We departed as the sky was beginning to lighten.
始める is the standard, everyday verb for 'to begin' and also forms the common compound auxiliary 〜始める. 初める is a more literary auxiliary with a similar meaning but a more formal, often written, tone.
Derived from the verb 初める (そめる), an older form related to 初め (はじめ, 'beginning'). The kanji 初 carries the meaning of 'first' or 'beginning'.