Japan’s Shinkansen bullet trains are a technological marvel – safe, punctual and, of course, very fast. But in the early models, traveling at such high speeds resulted in unwanted vibrations and noise. The “tunnel boom” problem in particular was causing a lot of head-scratching among Japan Railways engineers. As the trains sped through tunnels at over 320 kilometers per hour (199 miles per hour), they compressed the air ahead of them. The shock waves that this generated produced a loud boom audible from some distance away as the trains exited the tunnel. No-one had found an answer to this dilemma.

As luck would have it, the Director of Technical Development at Japan Railways, Eiji Nakatsu, was also a keen birdwatcher, and it was his love of birds that would provide the main inspiration for solving the problem. Nakatsu had observed the precision fishing technique employed by kingfishers as they dive from a lofty perch at high speed, entering the water silently and with barely a splash. He surmised that it is largely due to the streamlined shape of its bill that the bird is able to do this. After extensive testing and experimentation, the Japan Railways engineers came up with a design for the front end of the new bullet train model that was based on a kingfisher’s bill, giving the train its characteristic nose shape. This design meant that the new trains had 30 percent less air resistance than their predecessors and thus consumed less energy. Moreover, thanks to a small bird and Eiji Nakatsu’s observational skills, tunnel boom was now a thing of the past.