Since everyone is emphasizing on unique token address, now to be crystal clear:
Let's say i have issued 100 Gaming different swords each with unique attributes such as (attack value, power etc...) in this case every item will have its own unique address, now based on the repliers feedbacks the solutions seems to be as follows:
After creating swords (NFT) tokens the addresses of all created tokens should be saved in a database on the server, and then when the players tries to bring a sword into the game the system should check it the token's address is one of those addresses stored in the database.
Any item should have different uniq numbers. I think that you can see the implementation of NFT game like axie infinity, vulcan forged and some dapps game.
When someone wants to buy a sword and that guy must buy that and then some tokens as proof of ownership will be sending to the unique address that owned by the sword.
After his transaction gets confirmed and then the system will detect the sender and receiver address.