It comes from the establishment’s paper of unofficial record, so you want some corroboration, preferably from the Chinese side (not that the Chinese authorities will oblige), or Sankei.* Still, this latest Yomiuri report on the backstory for the omission of Asunaro/Longjing omission from the deal is intriguing. And encouraging too, since it drags South Korea into the picture.
According to the Yomiuri, the negotiators worried that South Korea, not a party to the negotiations, might complain that a Asunaro/Longjing gas well could suck gas out of deposits in/on the South Korean EEZ/continental shelf, on the other side of the China-ROK median line, so they’ve given up on the idea of developing the Asunaro field altogether, like a geopolitical AWAR. The story sounds a little fishy, since the South Koreans--their Sinophobia can sometimes make Shoichi Nakagawa look like a member of the fifth column for the Chinese Communist Party—haven’t been heard complaining much. Let’s hope the story is true, though, because it shows an awareness of the need to keep smoke off the waters—there’s always the threat of flames—among three peoples who share a common, resource-starved, trade-dependent destiny (among other things).
* My skepticism is given further ammunition by the thought: Why would the Japanese side have invested in yet another JV completely under Chinese jurisdiction, or the Chinese side accepted anything less, in the first place?