In the localization industry, Japanese is generally considered to be one of the hardest languages to get right. Extensive vocabulary, complex honorifics, multiple registers, and three different writing systems provide challenges during translation, while differing accents for East and West Japan can present issues when it comes time to record Japanese voiceover if not properly addressed with client stakeholders. So customers and language vendors need to be prepared, cooperate fully and know exactly who they are targeting.
Adding to the complexity; page layout, color, preference of image, illustration and graphics are all very different to the western world and all need to be carefully considered. Japanese client reviewers also tend to be highly specific regarding their stylistic preference, meaning that having Japanese in-house staff is a major advantage in helping establish a rapport and document stylistic preferences early on in a relationship.
This is just a snap-shot of some of the challenges that Japanese localization can present. More so than for any other language, selecting the right localization partner with demonstrated Japanese experience and a good understanding of the many pitfalls of Japanese localization is crucial.