This source names China directly: "on 24 October 1945 once ratified by China, France, the Soviet Union, the United Kingdom, the United States and a majority of other signatories."
Source History of the United Nations (UN)
This source names China directly: "and established the Republic of China."
Source Chinese Revolution, 1911-1912 (Britannica)
Source Constitution of the People's Republic of China (Wikipedia)
This source names China directly: "the United States, Russia, and China, are not parties, which has led to disputes over the Court's authority to issue arrest warrants against their nationals or leaders, and some African Union member..."
Source International Criminal Court (Cornell LII)
This source names China directly: "state to the 221 BCE unification of China under its First Emperor; the school's explicit political dominance receded after Qin's fall, though its administrative and legal machinery persisted inside..."
Source Fajia (Chinese Legalism), PhilosophyAtlas entity 116 and standard historiography of the Warring States period
Britannica names the Chinese Communist Party as a classic example of a hegemonic single-party ruler.
Source One-Party State (Britannica)
This source names China directly: "agriculture, and in Maoist China, distinguished from social democracy, which retains a market economy and private property alongside redistribution and a welfare state, by its direct state control..."
Source Command Economy (Britannica Money)
This source names China directly: "president of the Republic of China in 1912."
Source Sun Yat-sen (Britannica)
This source names China directly: "president of the Republic of China."
Source Sun Yat-sen (Britannica)
China is named as a unitary state.
Source WorldAtlas: What is a Unitary State?
This source names China directly: "It has fifteen members: five permanent (China, France, Russia, the United Kingdom and the United States) each holding a veto over substantive resolutions, and ten elected for two-year terms."
Source United Nations (Wikipedia)
China is one of the five permanent, veto-holding members of the UN Security Council.
Source UNRV Roman History: Tribunes of the Plebs