“In a brief online statement (link in Chinese) issued over the weekend, Beijing said the exercises will run from today (July 5) until July 11, finishing one day before a UN-backed tribunal issues a ruling on China’s sweeping territorial claims. China has long said it will ignore the ruling, and it refused to participate in the case, which began in 2013.”
Source: China Declares a No-Sail-Zone in Disputed Waters During Wargame – Defense One