Over the clatter of helicopter rotor blades and the powerful engines of tanks and self-propelled guns, an occasional "oooh" and "aaah" could be heard from the crowds of civilians in the stands at the Self-Defence Forces' training grounds on the flanks of Mount Fuji.
The annual drills, which started last Tuesday, are designed to demonstrate Japan's commitment to defending its territory and have become an increasingly important showcase of the military's abilities.
With Japan and China still locked in a dispute over the sovereignty of a crop of islands China calls the Diaoyus and Japan calls the Senkakus, it will not have been lost on the onlookers that the premise of the drill was an attack on Japan from the sea.
The exercises have also become more popular among aficionados of military hardware, which has found a growing following in a nation that has in recent decades been more keen to emphasise its pacifist and purely defensive credentials.
And anime characters - inevitably, in Japan - appear to be fuelling that fascination.
This year, a record 110,000 people applied for the approximately 6,000 places at the military exercises, with some suggesting the sudden sexiness of howitzers and squealing tank tracks is partly thanks to Girls und Panzer.
The animated show revolves around a group of girls - all of whom wear short-skirted school uniforms and have outsize doe-eyes - studying "the way of the tank," as if it were a martial art.
Sales of companion DVDs have been huge and the online game World of Tanks is a collaboration between the creators of the series and a computer game developer in Belorussia.
Plastic models of the girls' tanks have also been selling out at toy stores in Japan, while the town of Oarai, in Ibaraki prefecture, where the story is set, in March held a Girls und Panzer event as part of its annual spring festival.
Some even more well-known television characters have been used in recent months to promote careers in Japan's military, with the puppets from the cult British television show Thunderbirds being enlisted to encourage people to join up.
A series of posters were released in the spring that underlined the similarities in the tasks that face Japan's Self-Defence Forces and International Rescue Organisation.
One of the SDF recruitment posters features the five sons of Jeff Tracy in their matching blue uniforms, sashes and hats, along with Prince Pickles, the cuddly cartoon character who has been used by the SDF in previous campaigns, in his three guises as pilot, soldier and sailor.
Against a background of the five familiar craft that International Rescue use in their missions, a slogan reads, "Join the Self-Defence Forces and help the public!"
"The campaign has been effective and the collaboration on the Thunderbirds posters really helped to raise the profile of careers in the military," said a spokeswoman for the Defence Ministry in Tokyo.
In the last fiscal year, around 50,000 people applied to join the Self-Defence Forces, up from 47,000 the year before, and 43,000 applicants the previous year.
There are other factors, however, including a sense among young people after the March 2011 earthquake and tsunami that joining the armed forces would enable them to help the public in the event of another major natural disaster.
There was comparable motivation among people who applied to join Japan's coastguard last year.
Applications for places at the Japan Coastguard Academy in Kure, Hiroshima prefecture, were up 50 per cent on the previous year to 16,783, with young people increasingly seeing the work of the service as glamorous and exciting.