Can you use a fully Chinese deck at a tournament, and what are the language restrictions for decks?

Ruling: You can use a fully Chinese deck at tournaments. Each individual subdeck (main, legend, battlefields, runes) can be of any language, but all cards within the same subdeck must be in the same language.

Sequence:

• Each subdeck is evaluated separately for language consistency
• Within each subdeck (main deck, legend deck, battlefields, runes), all cards must share the same language
• Different subdecks can be in different languages from each other

Nuances:

• You cannot mix languages within a single subdeck
• A fully single-language deck (like all Chinese) is always legal