I do not know for the moment why Japan feels unease--or even "alarmed"
according to VOA Chinese--when China's submarines--with or without warships-
-approached--or passed through Okinawa islands.
The news reports below are in chronological order.
(1) Chinese submarines, destroyers spotted in high seas near Okinawa. Kyodo
News, Apr. 12, 2010. http://www.japantoday.com/category/national/view/chinese-submarines-destroyers-spotted-in-high-seas-near-okinawa
Note: This is the first time China's submar