Olive 21 is a “Couple Kissa” swingers club in that only accepts couples, no singles. They will not allow a man who doesn’t speak Japanese. You need to speak some Japanese and be able to understand the rules. You just need decent enough Japanese to answer their basic questions (and a lot of nodding your head yes and saying “Hai”) to the rules presentation. If you completely don’t understand Japanese, then they won’t let you in, because of the fear that a misunderstanding might lead to trouble. They also don’t tolerate rule violators there. With that stated, foreigners are allowed in.