However, economic cooperation among East Asian nations has been hindered by lingering distrust of Japan and the legacy of its imperial yen bloc.
The North China Economic Development Company was established with the aim of reducing non-Japanese economic penetration in North China, and the Chinese Maritime Customs Service was disrupted in an effort to degrade the credit rating of the Chinese government.
The intention of these measures was to sever North China from the rest of the country, so that "North China, like Manchukuo, will form a part of the gold yen bloc and a link in the chain of the currency system by which Imperial economies will be bound," as was stated by a Tokyo-based business journal.
[6] During the South-East Asian theatre of World War II, Japan took a more methodical approach to the expansion of the yen bloc, bolstered by experiences in China.
In 2008, Woosik Moon, a professor at Seoul National University, said that the experiences of the yen bloc during the Pacific War have hindered economic cooperation agreements in modern East Asia.