I have provided English to Japanese translations of safety-related materials (documentation and films), mobile and indie games, and independent films (Ashens and the Quest for the Gamechild, etc.) I have also supplied Japanese language voice-over for several small projects.
In most cases, it is preferable for a translation to be handled by a native speaker of the target language. Someone can have very high comprehension skills in their second language but their expression may lag behind. This does not mean that a non-native speaker cannot provide an excellent translation, but it is a good reason to be cautious of translators who say they can provide translations in both directions. Although I spent the majority of my life in Japan and speak Japanese at a near-native level, I am very selective about accepting work from English to Japanese. I will only accept a project into Japanese if I feel I can provide a translation that reaches the same high standards as I expect for translations into English.
If you are interested in English to Japanese translation services, please contact me via the enquiries form.