Learning something about Japanese culture will not only assist you in understanding the Japanese people better and therefore allow you to be more sensitive towards their culture during your visit, but it also makes for a much more rewarding trip.
Here are some posts we've written specifically about Japanese culture. In addition, you may like to check out the Japanese Festivals page, which describes the background to many of the country's biggest cultural displays.
Valentine's Day in Japan: Chocolate Just Got Complicated
White Day: Japan's Answer to Valentine's Day
Welcoming the New Year Japanese-style
Sweeping in the New Year: The Culture of “Osouji”
Bonenkai: “Forget the Year” Parties
Decision-making Made Simple: The Prevalence of Janken (Rock, Paper, Scissors)
Turning Swimming Pool Water Into Wine