"Chonmage" is the hairstyle of Japanese SAMURAI.
Many SAMURAIs tied topknot in Sengoku and Edo era.
And It was called "Chonmage" in Japan.
"Chonmage" disappeared with SAMURAI in Meiji era.(It's probably 1860~70s.)
You can see no "Chonmage" in Japan now except for dramas or anime.
But you can see the hairstyle similar to "Chonmage" even now.
It's the hairstyle of Sumo wrestlers.
That isn't strictly same hairstyle, but it closely resembles at some points.
If you want to meet sumo wrestlers, you should go to Ryogoku in Tokyo.
There is the Ryogoku Kokugikan which is their holy place in there.
I have previously worked there, I have seen them several times.