After implementation of many EPAs recently, traders tend to confuse in mixing up with EPA preferential tariff and GSP ("Generalized System of Preference") tariff.
Basically, GSP tariff is no longer valid after EPA implementation date. However, there are some exceptions, which makes the things complicated.
Even after the EPA implementation, if the items are not included in the EPA or the GSP tariff is lower than EPA tariff, GSP is still effective.
In addition, for Laos and Myannmar, all GSP rate is effective for both two countries.
There is very useful information list in MOF web site which provide "still effective" GSP rate items after EPA implementation. (in Japanese only)
Traders who have used GSP rate need to check this site.
(Source: METI web site http://www.meti.go.jp/policy/trade_policy/epa/GSP.pdf )