150 years ago,when Western countries came to East Asia to colonize it,it was only Japan150 years ago,when Western countries came to East Asia to colonize it,it was only Japan which could confronted them.it was only Japan which could confronted them.这里的it是指什么

150 years ago,when Western countries came to East Asia to colonize it,it was only Japan
150 years ago,when Western countries came to East Asia to colonize
it,it was only Japan which could confronted them.
it was only Japan which could confronted them.这里的it是指什么