So, should we enter the Japanese market?
The short answer is yes if you have a novel product. The reasons are...
There are very very few local companies who have innovative products. In other words, the market is not as mature/crowded as your local market. Actually, there are only 4 companies on CB Insights' Unicorn Company List. The customers in Japan are demanding novel products but local companies are not able to fulfill the needs. So, there are unfulfilled and unrealized needs in here.
The customers are loyal and sticky once you start to working with them. (Though, they may be noisy customers on quality, price, etc. etc.) I often had heard comments from senior management people telling me that "We'd like to do business with you if you keep operating in Japan for next 10 to 15 years." Yes, they are seeking long term relationships.
You will be able to win the market over your strongest competitors if you move quickly, wisely, and effectively. You will be amazed to see that Yahoo! is still one of the most popular website in Japan. I don't know any single person who don't check Yahoo! News daily basis in here... Also, Facebook is used as the top business SNS while LinkedIn is really struggling in the market.
Yes, we speak different language and have different culture, but we have same desire that we want to utilize technologies that will make our life better. So, if you've succeeded to build new market category by introducing novel technology in your local market, I would say that you have high probability that you will be successful in the Japanese market.
Hope to have a chat if you're interested in Japan market entry.