一板三眼

一板三眼比喻有規有矩，做事有紋有路，有多少死板，不懂轉彎〔不靈活〕。板眼是中樂節拍。
一板三眼describe a person performing a task with good steps, skills. He knows how to do thing in proper way. Negative notion is not flexible enough. 一 is one, 板眼 is musical bits, notes, 三 is three. 板 is sheet of wood and 眼 is eye for direct meaning.