19.4.1.23:59: THE DAY OF THE YELLOW DRAGON

Or, in Jurchen,

<YELLOW.nggiyan DRAGON DAY> songgiyan mudur inenggi

Today Chief Cabinet Secretary 菅 義偉 Yoshihide Suga revealed the new Japanese era name 令和 <GOOD HARMONY>¹ Reiwa that will begin a month from now. ('Now' is Alofi time so I can finish this on 1 April!)

So much has been said about that name in just one day. Hence I might not be the first to say this:

Could the Old Chinese word *Cɯreŋ 'good' written as 令 be cognate with the far more common Old Chinese word 良 *Cɯraŋ  'good'?

OK, I doubt anyone else would reconstruct the two words that way. But the two words are similar no matter which reconstruction one uses. They're even similar to this day in Mandarin: líng and liáng.

There are two problems with my claim:

First, what is the significance of the two different root vowels? I have no explanation. I would feel more justified in linking the words if I had other examples of *a ~ *e alternation with identifiable functions.

Second, did the words really have the same initial consonant in their presyllables? If not, what would have been the significance of different prefixes?

I need the high-vowel presyllables to account for the diphthongs that the words developed in Middle Chinese:

令 Old Chinese *Cɯreŋ > Middle Chinese *Cɯrieŋ

良 Old Chinese *Cɯraŋ > Middle Chinese *Cɯrɨaŋ

¹Why is this name already in Windows 10's Japanese IME!? Was it added in an update?