As a sporting Terrier the Japanese Terriers can excel in many venues. There are a number of them doing great things in both the show and performance rings in Japan. The Japanese Terriers can be seen in sports like conformation, frisbee, agility, flyball, and Japan specific dog sports. 

They are smart dogs that catches thing quick, and with the right training tools and strategies they will make great prospects. 

I do not recommend this breed for anyone specifically looking for water sports or service works. Majority of them do not like water, which I suspect comes from one of their foundation breed, native Japanese/Spitz breeds. With the temperament of Japanese Terriers they are not suited for service work, and I expect handlers to have a big challenges with them. There have also been zero Japanese Terrier used specially for service works so far. 

My dogs are competing in conformation, barn hunt, agility, and lure coursing with plans to dabble in more.