Is the historical 9 18 event a solar calendar or a lunar calendar?

The historical 9 18 event is Gregorian calendar 193 1 September/year 18. The Japanese Kwantung Army stationed in the northeast of China suddenly attacked Shenyang and occupied the northeast by force.

The sound of guns on September 18 shook the land of China and aroused the anti-Japanese anger of the people of China. People from all walks of life all over the country have called for resistance to Japan and opposed the non-resistance of the Kuomintang government. Newspapers headed by Shenbao have raised a call in China to boycott Japanese goods and demand resistance to Japan and national salvation. People in Northeast China rose up to fight against Japanese guerrilla warfare, and Northeast Volunteers and other anti-Japanese armed forces appeared one after another.

China * * and the red regime he led issued the strongest voice against the Japanese aggressors, which is in sharp contrast with the Kuomintang's non-resistance policy, indicating that China * * * has become a powerful force against the aggressors and is also the mainstay of War of Resistance against Japanese Aggression's national victory in the future.