Standard disclaimer: This is probably illegal, and despite being virtually foolproof, you should never do it.
An additional scam is to use two sets of "multiple trip tickets". For an example, imagine that you regularly travel between Utsunomiya and Tokyo, a trip that would normally cost 2,000 yen each way. Here's how you do it:
- Buy a multiple trip ticket which is valid for 11 trips between Utsunomiya and the closest town (Suzumenomiya). This costs 1,800 yen.
- Buy a multiple trip ticket valid for 11 trips between Tokyo and Ueno (a suburb very close to Tokyo station). This costs 1,300 yen.
- When entering the platform in Utsunomiya, use your Utsunomiya <-> Suzumenomiya ticket.
- When exiting the platform in Tokyo, use your Ueno <-> Tokyo ticket.
Utsunomiya <-> Suzumenomiya Ueno <-> Tokyo
<--------- 164 yen -------> <-- 118 yen -->
<--------------------------- 2,000 yen -------------------->
Multiple trip tickets are valid in both directions of travel, so you can use the same set of tickets to travel in either direction. They are valid for three months from the day of purchase, whereas a regular single trip ticket must be used on the day of purchase.
This can make regular journeys very cheap. In our example, a 2,000 yen journey will cost you only 282 yen. In addition, there is virtually no way of getting caught. Every time you enter and exit a platform, you are doing so with a ticket that appears entirely valid, and beyond suspicion.
There are a few difficulties however. One is that conductors will occasionally patrol the trains, checking for tickets. This is a very rare occurrence, and if does happen you will be forced to "upgrade" your ticket, and pay full price for the journey. The second is that multiple trip tickets can only be purchased at either of the two stations that the ticket is valid for. This means that you may have to pay full price for your first trip, or alternatively get a friend who lives in that town to buy the multiple trip tickets for you, and mail them to you.
Although this system appears inflexible, by combining it with the ability to legally upgrade an insufficient ticket at your destination, you can extend its usefulness.