According to a recent article in a Korean newspaper, Colin Renfrew and Paul Bahn's Archaeology: Theories, Methods and Practice, now in its seventh edition, has revised its description of the origin of domesticated rice. While "before 2004" this popular introduction to the academic field of archaeology had rice from 9,000 BC discovered in China's Hunan province as the oldest example, in the latest edition it is supposed to have changed this to rice from 13,000 BC discovered in the Sorori site in Cheongju, South Korea.
I have to say I really doubt the claims in this article, given that the there was strong skepticism in academia about the Sorori rice claims that were first publicized in 2003 and even led to a BBC article, but which smack of a nationalist agenda. I wouldn't be surprised if the whole article was a fabrication or the product of some sort of a wishful misinterpretation. However, I don't have access to Archaeology, so I'm wondering if any redditors can tell me what it really has to say on the subject.
In the chapter on rice farming in Khok Phanom Di, Thailand (pages 531-537) Renfrew & Bahn mention the site you are referring to. But it's in a parenthetical and qualified with the words "appears to be":
Settlement at the site itself [Khok Phanom Di] proved to be too late (2000 BC) to overturn the conventional view that rice cultivation began further north in China, in the Yangzi Valley, between 10,000 and 5000 BC, and spread south from there (indeed, what appears to be even earlier domesticated rice has recently been found in Korea, dating to c. 13,000 BC). p. 537
There are a couple of other references to rice domestication throughout the book; none of them mention Korea.
A separate development, based at first on the cultivation of millet, seems to have taken place in China in the valley of the Huang Ho by 5000 BC. Rice cultivation began at the same time in the Yangzi Valley in China and spread to Southeast Asia. p. 169
In Japan, about 500 ancient rice paddy fields have been discovered, especially from the Yayoi period (400 BC - AD 300), together with their irrigation systems - wooden dams, drainage ditches, and balks. Far older rice fields have been unearthed in China, at Chengtoushan in Hunan Province, dating back as far as 6500 years ago. p. 265
Chemical analyses of ancient organics absorbed into pottery jars from the Early Neolithic village of Jiahu, in China's Henan province, has revealed that a fermented drink of rice, honey, and fruit (possibly grape) was being made as far back as 9000 years ago. p. 281
All quotes from: Renfrew, Colin, and Paul G. Bahn. Archaeology : Theories, Methods and Practice. Seventh Edition, Revised & Updated ed. 2016.
I'll have the book on hand for a couple more days, so if you have a follow up question don't hesitate!
Edit: formatting