The Tokyo Metro has been boasting in its carriages that mobile coverage within the underground tunnels is being improved.
Those used to the subway in New York City or Washington D.C. are often impressed with the ability to get a signal in the stations.
Those from South Korea are spoiled: not only do they have cell coverage in the tunnels but many of the subway cars in Seoul have Wi-Fi.
The three men representing the signal bars are doing three different things with their phones in the tunnel: work, love, and play. I do two of those three things.
The small print warns that the cell usage in the trains should be data only, not done near the priority seats, and may be spotty in some areas.
Indeed, when I tried it out on the Chiyoda line, the reception was much better than usual, but I was unable to maintain a streaming video without interruptions in the dead middle of the tunnel.