also: どおりで
Ah, no wonder it was quiet. Everyone had gone out.
彼は毎日練習している。どうりで上手なわけだ。
He practices every day. No wonder he's so good.
Kanji spelling is understandable but less common than kana.
Irregular kana variant; recognized but not standard.
Derived from 道理 (reason, logic) + で (particle), literally 'by reason'. The kana spelling is now standard.