I'm having some trouble finding out how many case marker particles (格助詞) there are in Japanese. The answers I find range from 9 to 11, depending on the site. Almost all of the ones I've found agree on the following:
が、で、に、を、へ、と、より、から、まで
The 2 that seem to be contested are の and や. I understand a particle belonging to several classes, but I don't know why some sites leave those 2 out entirely. Is this simply something that Japanese speakers and scholars disagree on?
Sources
The following site says there are 9:
https://www.tomojuku.com/blog/kakuparticle/
The following say there are 10:
https://prowriters.jp/grammar/postpositional_particle#1fc6088c4182e88f2092d7ba4b537282
https://note.com/kokugo_nihongo/n/nbdbe46679247
This site says there are 11:
http://www.coelang.tufs.ac.jp/mt/ja/gmod/courses/c01/lesson14/step2/explanation/053.html