A dizi is sold in a physical key. On the common six-hole instrument, that printed key names the pitch made with the three holes nearest your mouth closed and the other three open: XXXOOO. It does not name the all-closed note.
01 Start with D or G when your teacher or repertoire does not specify
D qudi and G bangdi are common reference points. D sits lower and is often physically longer; G sits higher and is often more compact. F also has direct modern acoustic study. The best key is still the one required by your teacher, ensemble, or chosen score.
02 Read the fingering before trusting a tuner label
Cover the three holes nearest the embouchure and open the other three. Hold a clear tone and compare it with the printed label. As a cross-check, all six holes closed should sound about a perfect fourth lower. A beginner's lowest note can be unstable, so manual selection is more trustworthy than forcing a weak automatic result.
03 Why the exact cents move
Bamboo maker, embouchure, breath pressure, temperature, humidity, and the dimo all change the measured pitch. A tuner target is a starting line, not proof that every handmade instrument follows one factory profile.
04 What 筒音作5 means
Under the home 筒音作5 frame, the all-closed note is low 5 and XXXOOO is 1 — the instrument's named key. Other Tong Yin assignments reinterpret the same physical pitch map; they do not retune the bamboo.
Evidence: measured Dizi impedance/fingering work from the SUTD/NUS open dataset and the Shanghai Conservatory orchestration annex. Transposed targets still need checking on the real instrument.
Related reading
Questions
What is the most common dizi key?
D and G are common reference instruments; choose the key your teacher, ensemble, or score requires.
Is all holes closed the dizi key?
No. On the common home fingering, XXXOOO names the key and all closed sounds about a perfect fourth lower.