memorandum
Infer information that cannot be observed only by you from the behavior of others game. Similar to [coyote (carnivore, Canis latrans)
There are one 1 to seven 7s.
It depends on the number of players, but for 4 players, 5 cards in hand, 4 cards in the field, and 4 cards face down.
Only you can't see the cards in your hand.
Declare one number each turn.
If the declared number is in your hand, it opens one card.
When fighting a typical person, it is possible to have a better chance of winning if you play ignoring everything (except level 1) rather than trying to guess from the opponent's behavior.
Unless you take notes, which I don't do in the basic playstyle of this game, you're going to have to rely on your memory of flesh and blood. Using information from someone else's point of view is computationally complex.
High risk of confusion trying to do something complicated.
Level 1 play briefly explained
First check the frequency of the numbers on the field to see how many you don't see.
It's seven numbers, so think of it as a phone number and you should be able to remember it.
The higher this number, the more likely it is to exist in your hand.
in order of precedence
If any, reduce by 1
If no, set to 0
The frequency of being on the field can be restored by re-counting, even if it is forgotten.
It is necessary to memorize the information about which number you said was the wrong number, because it is not left in the field.
Level 2 Play
Use information from other people's perspectives
After doing the first frequency count on level 1
For example, if the number of 1's left from your point of view is 1 and someone else says "1" and it is a hash.
If the number of 1's remaining is not 0 in the eyes of others, then there is no 1 in your hand.
That is, the number of 1's left.
As for 1, it's obvious, but as for 4-7, you need to discount the information because you don't know if your opponent is playing level 1 properly or if he's just confused and saying random things.
If your opponent is playing level 1, for example, if you have two 7s left and one 6, and he chooses a 6, the probability that you have a 7 in your hand that he can see increases, but most people are not that reliable.
Decent level 2 play
At the start, if you have 4 face-down cards and 5 cards in your hand, you have $ _9C_5=126 street possibilities.
It can be smaller than this because of overlapping numbers.
At first, all of those possibilities are equally probable.
If the opponent says "1" (a), the probability is reduced by the inference that "the probability of doing that in case x would be low" for "event x in which your hand contains 1".
$ P(x|a) \propto P(a)P(a|x)
In this way, the conditional probability conditional on all observations is updated for each additional observation.
As for your own hand, just ask for the probability of the existence of 7 different numbers and say the one with the highest probability.
Programmatically, it's easy, but a flesh-and-blood human being would have difficulty holding 128 values in memory and multiplying each one.
---
This page is auto-translated from /nishio/ドメモ using DeepL. If you looks something interesting but the auto-translated English is not good enough to understand it, feel free to let me know at @nishio_en. I'm very happy to spread my thought to non-Japanese readers.