Yu-Gi-Oh! has released some genuine Traditional Chinese cards since 2014, but there are very few types and they have not been updated for a long time, so it is difficult to see them. You can tell whether a Chinese card is authentic or fake by the following methods.

There are words on the back, the upper left is the word "KONAMI", and the lower right is the "Yu-Gi-Oh" (traditional Chinese) trademark. No words, "GAOQIAO", "KQNAMI" and other words are pirated.

The card number in the lower right corner of the card picture. The number of the authentic Chinese card should contain "TC".

The attack power and defense power of genuine cards are represented by "ATK" and "DEF" instead of Chinese characters.

The monster attributes and magic trap marks on the upper right side of the genuine card should have phonetic notation.

All genuine cards that have been sold can be checked on the ourocg website. If they cannot be found, then they are cards made by pirates.

Price and sale form. The price of genuine supplement packs is generally about 10 yuan per pack, which contains 5 cards. The pre-assembled price of 40 sheets is about 80 yuan. Genuine Chinese cards do not have tin boxes. The common 5 jiao, 1 yuan and other card packs on the market are naturally pirated. "Youth Hall", "Takahashi", "Game Kingdom", etc. are all common pirated brands.

In addition, the workmanship details of pirated cards are quite different from those of genuine cards. If you can get a genuine card, it will be easier to identify them.

Reference materials: Here is the web link where you can find all the card packs, cards and effect texts that have been sold in the Chinese version. You can compare with this to identify the authenticity of the cards.