https://memory-sports.com/blog/interviews/interview-with-shijir-erdene-bat-enkh/
Memory-Sports : Please describe us your number system and why do you use it.
Shijir : I use PAO (Person-Action-Object) in my number system. I use it because that is the first main system that our memory school teaches us and it feels comfortable and interesting to use.
Memory-Sports : Please describe your card system, with which you broke the Junior world record in Speed Cards at the US Open 2016.
Shijir : I use the PAO system in cards as well.
The “memory school” he mentions is once more the Mongolian Intellectual Academy, where most the top Mongolian competitors started out… I pointed that out before in this thread:
The record mentioned in the interview was at 23.22 sec from 2016, so not the one in the video. Maybe he has upgraded to a two-card system or maybe he’s still using PAO.
I’m not sure what you mean by chaining… if you mean from one image to the next, that doesn’t happen… you just place the compound image at the next location in the memory palace. Nobody at these speeds uses the linking method.
If you mean how he can combine P, A, and O into one image… consider a young child learning the alphabet and being amazed by how some adult can read really long and complicated words… sometimes even whole sentences in the same time that child puts together consonants and vowels to form a word.
The math in case of a PAO system: place one image per location (3 cards) for 17 locations. For the Junior record at 23.22 he spend just over a second at each location.
Assuming a 2-card system: place two objects (double-card each) in, on average, 13 locations. So that would be just under a second with the record in the video.
Usually you don’t encode the last three or so cards, but rather form the image after you put down your deck and stopped the timer. Also you get the remaining time of the 5 mins you have to memorize the cards that you can go over the whole memory palace again a few times before starting the recall.
Bear in mind that you can place very soft Images during the initial run with the timer and then strengthen them when you go over them again for the next 4 1/2 minutes. So it’ll take less time to place the image initially.