I remember of other efforts by other nations, and some of the same, to attain similar zones though the exact details I no longer have on hand.
I know that, in the case of the United States, Secretary of State John Hay had tried to attain a lease on some bay area between the area of Taiwan and Shanghai; this effort was halted by Japan however who had their own designs on the exact same area and, in a bit of an ironic twist, cited the Open Door Policy as the reason for their opposition.
I also know that Italy had also attempted to obtain a lease but was rebuffed by the Chinese.
Just curious if anyone has any details on those two efforts, or if there were others that I may not be aware of.