Excerpts from Books and Wikipedia
"21 Demands (1915): The Japanese attempt to close the 'open door' by demanding exclusive industrial and commercial rights in China." [Fall and Rise of China Guidebook, p. 199] "Japan's aggressive 21 Demands of 1915 tried to set up a sort of Japanese protectorate over China. Though not successful, this incident ended Japan's era of reform leadership in China and heightened China's modern nationalism." [Fairbank: China, p. 266]