The answer to this question is "Yes", Japanese is one of the most difficult languages to learn and to master. Regardless of what you've heard, regardless of what you've read and regardless of how many "Learn Japanese in 10 days" book titles you've seen at the library, the Japanese language is extremely hard to handle for most of the Western world using Anglo-Saxon or Latin lexicons. The Japanese alphabet (which is a combination of 4 different alphabets and scripts), the Japanese grammar, high pitched Japanese pronunciation of words and the distinct speaker - listener status that is specific to the Japanese language are all factors that can guarantee you'll have a harder time learning this language than say, German, French, Spanish or any other language that at least shares some common attributes with English.

But then again, if you've set off to learn Japanese, you're either very ambitious, or you're forced to learn it because you're moving to Japan, visiting Japan, your business needs to handle contracts with Japanese firms or any other similar reason, so you can't let the detail of the language being "hard" to stop you. After all, you're part of a select group of foreigners learning Japanese. Why I'm calling you "select" is that studies show that only around 2.5 million people learn Japanese in institutions (1.5 million being South Korean and Chinese, with only 300,000 Australians, 150,000 Americans and 200,000 Europeans) and another million studying it on their own. Although we're talking about millions of people, the numbers are still low compared to other languages such as English, French, Spanish or German, which are being studied by hundreds of millions at a time.

Depending on your language learning skills, on the quality of your teachers, courses, books and the amount of time you spend on learning Japanese, it could take you between 2 and 4 years to say that you've mastered it. Visiting Japan or staying there for a longer period of times obviously helps a lot and makes your task easier, as is with most languages. Also, if you're studying Japanese for a business purpose, you'll have to handle specific terms which most general Japanese courses don't cover. For these, you either need specialized courses or you need to fill in the gaps by reading on the subject.

Whenever you think you're ready, you can try taking the JLPT (Japanese Language Proficiency Test) or JETRO (Japanese External Trade Organization), offered by the Japanese government. These tests are paid and they are quite hard for even an intermediate Japanese student, so they're not worth wasting your time unless you're 100% confident on your Japanese language skills. If compared, you can say that the JLPT is similar to any other high level language certificate such as the English CAE (Cambridge Advanced English) and TOEFL (Test of English as a Foreign Language), the French DALF (Diplome Approfondi de Langue Francaise) and DL (Diplome de Langue) or the German GDS (Groses Deutsches Sprachdiplom).