For those looking for a more mainstream approach, the large number of gaijin bars that are frequented by both Japanese women and men hoping to meet foreigners are one of the most popular choices, but keep in mind there are usually more foreigners than Japanese present, and the competition can often be fierce. Another method of bringing Japanese and foreigners together are “International Parties” that are often advertised in magazines and newspapers. For a set fee of approximately 5,000 yen you're able to attend a prearranged party in a restaurant or lounge where you have an opportunity to mingle with others interested in cultural exchange. In a similar venue are international hiking clubs that are now a popular form of meeting people, as most day hikes in the countryside are arranged with an equal number of men and women in mind. Sport clubs still appeal to many people who hope to meet others between workout sets, and the recent influx of Starbucks coffee shops in Japan are usually packed with Japanese women and men who are alone and receptive to conversation.
It's difficult to discuss cross cultural differences without making generalizations that may or may not be accurate as each case is different, but for the most part Japanese are usually approachable in a social setting even if they appear to be a bit shy or reticent at first meeting. Foreigners who speak Japanese well are obviously going to have an advantage over those whose language skills are limited, and many relationships in Japan fall to the wayside eventually because of this lack of communication. Though mutual attraction is sometimes enough to keep a couple together, those looking long term usually have a better chance of success if one or both partners can speak the other's native language well. As is the case in most Asian countries, age difference between men and women in Japan is not looked upon as an issue, and you often see couples together whose presence would no doubt turn heads in other parts of the world.
The Japanese view of sex is also quite different from that of the west, and they usually approach it with a more relaxed attitude, as can be witnessed by the large number of “Love Hotels” found in all major cities of Japan which provide a temporary haven for couples in need of privacy. This cavalier attitude can also sometimes be confusing for foreigners, who after becoming infatuated after the first or second date will suddenly find their email and phone messages going unanswered. Though definitely not pleasant for the ego, once it's understood the Japanese are uncomfortable with direct confrontation and this is their way of letting you and themselves off the hook, it's usually a bit easier to comprehend and accept. This approach often pertains to long term relationships as well, and there have been many foreigners who after years of being in a relationship suddenly found themselves in the cold for no apparent reason and with no explanation forthcoming. Society's view of international relationships in Japan seems to be that of resigned acceptance, but don't be surprised if there is resistance on the part of many Japanese parents in regard to their son or daughter marrying a foreigner. Although this attitude has gradually begun to change over the years, most traditional Japanese still want their children to marry Japanese.
Source: http://www.amazines.com/Travel_and_Tourism/article_detail.cfm/393669?articleid=393669