This page will be about Mr Hara Yasuhisa, author of Kingdom, and the information he provide us through the various interviews, lectures and stuff.
There was an interview with Mr Hara, author of Kingdom, in a television program in Japan. As there are no more active links I can find for the interview video, I guess this is the only thing left of the interview on the internet.
According to the guys in Chinese forums(thread here: http://tieba.baidu.com/p/2811437379), here are some information provided by Hara sensei：
1)Kingdom almost had to stop serializing around volume 3-4(i assume due to poor sales). Hara sensei then went to look for Inoue Takehiko for a drink. Mr Inoue then gave him some advice on how to improve his art.
You guys can compare the art style for the first 4 volumes with that in the later volumes to see the difference.
2)Mr Hara: Looks like everyone seem to like Ouki and hate Riboku. I would be happy if someone tell me he likes Riboku…(Mr Hara is a fan of Riboku). The host then mentions that he likes Kanki and Ousen.
3)Mr Hara said that whatever was clearly recorded in Shi Ji will not be changed in the manga(eg. year xxx, so and so happened).
Looks like somebody is definitely going to be defeated in Chu…
4)Mrs Hara participated in the Social Kingdom project too. Refer to the top left panel of the second post of the tieba forum thread above.
5)Mr Hara went to China himself to look at the ruins of ancient China before he started drawing Kingdom.
6)Ousen and Tou will have plenty of spotlight in the future(well not too surprising…)
7)As of now(~chapter 370), the manga is almost half complete(~40% according to the OP)
8)There are too many members in Hi Shin unit and Mr Hara had to put a drawing of each member on his wall so he doesn’t forget who is who.
9)Mr Hara’s favorite duel is the duel between Moubu and Kanmei and his favorite deaths are tied between Ouki’s and Rinko’s.
If you are too lazy to watch the video or cant watch at all, there are some pictures of the interview in that tieba thread above, including Mr Hara’s studio(or house) some of his drawings and some drawings other famous mangaka gave him. Those 5 books in white cover that he is holding are Shi Ji lol.
Original mangafox thread: Link
Mr Hara also conducted a lecture at Kyushu CEDEC 2015, giving us some insights on Kingdom manga’s history and his life. More information of can be found here:
Mr Hara Yasuhisa’s lecture at Kyushu CEDEC 2015
Japanese TV show,情熱大陸, interviewed Mr Hara on Oct 30 2016, giving us a peek on his life as a mangaka and on the Kingdom universe. Detailed post can be found here: Interview with Mr Hara (Oct 30 2016)