These patterns have pages on the Wiki. The infobox lists how commonly they're found within a non-standard variant's ruleset (or its value in a standardized ruleset).
The non-standard variant scale goes…
- Always: No known rulesets omit it.
- Common: At least one known ruleset omits it.
- Uncommon: A few omit it, a few have it.
- Rare: At least one known ruleset has it.
- Never: No known ruleset has it.
- N/A: Not applicable (generally for Taiwanese)
Q: "I've seen a Chinese Classical ruleset that has such-and-so pattern, but the wiki says 'Never'. What gives?"
A: Many people refer to Shanghai "New Style" rulesets as Classical when they're actually contemporary to Classical.