I just finished my Japan and Korea Trip last week. It was 21 days. 12 days in Japan, and 10 days in South Korea. I'm gonna write a long story about this trip later after I finished compiling my travel pictures.
First of all, the most important information that I want to share is how to get the South Korean visa free for Indonesian passport. You know that for Indonesian passport holder it is not easy to go to some places, because of the visa restriction. We have to apply for the visa to enter South Korea and Japan. Applying visa means we have to go to the embassy, provide bank account statement, recommendation letter from company (that I will go back to Indonesia without seeking for any job in the destination country), etc. Not very convenient, and collecting all the requirements is really taking time, that some people just gave up applying that.
But! if you're on transit (or stop over) and have some eligible visas that haven't expired yet to some of the listed countries, you don't need visa to enter South Korea! How nice is it?