To wit: the Mint will also sell you in line with Chinese numerology collectible bills with “777”s or “888”s in their SNs with a decorative envelope. Bless the marketing exec who’s finding nontraditional markets for collectible currency.
Sevens are a massive number in Chinese numerology: The 7 parts (yin/yang/metals), the 7 steps, 7 captures, etc.
Eights are symbols of prosperity, wealth, generosity, good fortune in business, etc.
Six is a kinda useless number for money -- Smoothness and whatnot are less for money and more for one's tongue. You'd name a wine after a six (I've seen "Dice Wine" referring to 6-sided dice) but not look for it in bills
Well, https://hsbc.banklocationmaps.com/en/chn/shanghai only lists one branch at a street address of 666, and that one is really just sharing the address of the commercial center where it's located, but that still seems like enough for this point.
8 is heavily represented. 6 is a runner-up. 7 doesn't appear to be significant in this context.
Consider the branch phone numbers:
3888 3888
3888 8468
3888 8900
3888 1200
6279 8582
3888 3111
3888 1318
3888 1188
3888 6455
3888 8618
3888 8688
3888 1218
3888 6388
There is technically one 7 in there, but it seems clear that the bank would have preferred not to have it. Counting only the second halves, 8 is overwhelmingly popular, so is 1 (for reasons I don't know), 6 is only barely ahead of what's typical, but still in third place, and 7 doesn't even exist.
For those who are interested: the Chinese character for 8 is a pair of downward lines, close together at the top, far apart at the bottom. Looks a bit like / \. The idea behind it, as far as I know, is that it represents things growing larger, which is why it is of interest where wealth is concerned.
