Keiō 1DAY Ticket
Keio Corporation operates a rail network that spans Tokyo and extends to neighboring prefectures. The company's "Keio 1DAY Ticket" can be purchased from automated ticket machines at all stations, starting from the first train of the day. (Note: Sales times are limited. If no information is displayed on the ticket machine screen, please ask a station member.) If purchased on the same day, you can use this pass for unlimited rides on both the Keio and Inokashira lines.
It was my first time going to Mt. Takao, and getting this 1-day pass made everything so much easier and saved me money!