There was no official ranking for the world's top memory masters because the title of memory master was very honorable and difficult to be officially recognized. However, there were some famous memory masters like Harry Potter, Nicolas Tesla, and John Bartolomeo who were widely regarded as geniuses in the field of memory. The memory master's memory methods included the following: 1. Associate memory method: connect the information that needs to be remembered with existing knowledge or experience to form an interesting association to make the memory more profound. 2. Story-based memory method: connect the information that needs to be remembered with an interesting story or plot. 3. Image memory method: By drawing the information that needs to be memorized into images or symbols, it makes the memory more intuitive and profound. 4. Breathing memory method: Keep yourself in a positive state of mind and focus during the process of memorizing information by repeating and hinting. 5. Encode Memory Method: Transform the information that needs to be memorized into numbers or symbols that are easy to understand and remember, so that the information can be memorized by code. It should be noted that the memory master's memory method is not omnipotent. Everyone's memory ability varies greatly, so you can try and practice more before memorizing to find a suitable method for yourself.