Regrettably I haven't posted as much in this thread as I would have liked to in recent years. And yet the project really has come so far. I now have access to more information than ever before, I've gotten my hands on troves of county chronicles and Guo Tingyi's historical timeline of the Republic of China.
I remember the early years of making the warlord atlas, where I was still very inexperienced and my sources consisted of wikipedia and a few unreliable websites. Frequently it was impossible merely to ellucidate the ownership of a whole province. Over the years I gained access to more information, such as
this website with a complete list of provincial governors. And by now, I am worrying not about provinces (of which there were 28 in 1929) but about counties (of which there were 2,045 in 1929). So the precision I can produce has increased by two orders of magnitude. However this presents a new problem, which is that there is so much information that making maps from it has become prohibitively time-consuming. This is why I have submitted few maps here in the past few years. The QBAMs are the best work, but they are rushed, not very detailed, and hard to interpret due to the lack of labels.
Currently I am working on a project convering the whole history of Shaanxi province from 1911 to 1953 (previews have been posted above, though I have had to re-do the whole project so far slightly so those may not be completely reliable). I cannot make any hard promises, but if the current rate of work can be sustained, it could perhaps be released sometime in March. It is being made in youtube video format. I intend to continue in this manner for each province, and at the end of the process, it will finally be possible to make a third edition of the warlord atlas. That will be years from now, but that version would hopefully be more or less definitive.