I read a manga and one panel showed a swimming pool. Some readers commented "didn't expect to see that pool here" and no one would tell me where the pool was from. I presume it was from an anime or other manga
just wonder which swimming pool is so famous that people refer it as 'that pool'
From Ya Boy Kongming!, Chapter 63, page 6
This pool exists in real life in the Hanazono Room. Its internet fame comes from a not-very-surprising origin, which is its prevalence in pornographic material.
With images of the swimming pool of the Hanazono Room got from pornographic films circulating in local Japanese internet community by late 2000's, it began being referred to as "That Pool" (あのプール ano puuru) and "The Pool" (例のプール rei no puuru) among Japanese internet circles, most especially in 2ch and NND.[6] Not long after, news outlets also began referring to the indoor pool as "That Pool".[7] As names of the indoor pool became popular on the local media, the P-Studio which operates it eventually adapted the name "Example Pool". At some time during the latter half of the 2000s, several segments from television drama Kamen Rider Fourze also featured the indoor pool, resulting to the pool garnering even more fame in media.[3] With the massive spread of Japanese pornographic films on the internet around early 2010's onward, including the swimming-themed poolside pornographic films that were shot on the pool, "That Room" finally earned a global following and eventually became a well-known internet meme and gag as segments of the global internet community gradually familiarized the unique design of its surroundings in relation to its cult-like status on the web specifically in regards to the Japanese pornography industry.[8]
So yeah, basically, this pool was featured in a lot of porn, got famous on the internet as "The Pool", and now various other media, pornographic or not, refer to it as a sort of inside joke of sorts.
