@UlrikeFischer I breaked it down to the current main-problem, see comment here: https://tex.stackexchange.com/questions/630888/chessboard-creating-and-positioning-a-red-king-new-piece/630890#630890
This seems to me as a alignment with hardcore LaTeX submissions. I don't know enough about that. If that were a pgf thing, I would probably only have to say align=center somewhere or that would be the default anyway.
@cis even with pgf you would have to fiddle with the alignment. Symbols for boards and symbols for running text have different requirements regarding their dimensions.
@Rmano Operator error: there's no grouping of units in siunitx at all, so when you do \per<some-combined-unit> you are just applying \per to whatever comes first
@cis well it is a rather large package with a long documentation. So yes, you won't master it in 10 minutes. And if you only need colored kings, then why don't you color the existing kings?
It is probably completely clear that this has no effect at all and certainly only works in connection with various tricks that require decades of LaTeX experience. Yes, my mistake...
@cis When things become complex like those, I normally end up writing a python script that generates the LaTeX. (I know, I should learn Lua). Often it's the easier way.
@cis page 3 of the documentation, below the "attention". And yes: I do expect people to read a documentation. chessboard is not intuitive and you can't use it by simply copying an example without reading the surrounding text. It has some unusual concepts and fonts aren't a trivial subject in pdflatex either. Use something else.
@MarcelKrüger is there an luaotfload update waiting? There is a remark from Robert on the mainsite about something in the dev version regarding microtype.
