Because opaque bags such as briefcases cannot be brought into the Tokyo Main Library and the Kansai-kan, before entering the library the user is required to deposit his/her baggage in a locker located next to the entrance.
なお、東京本館と関西館では、鞄などの不透明な袋類の持込を禁止しているため、入館前に荷物は入口脇にあるロッカーに預けなければならない。