That bad boy pictured above is the Yonshakudama (Four Shaku Ball) and it claims to be largest single firework in the world. At a pot-smoker pleasing weight of 420kg (926lbs) and with a diameter of 1.2m (4 feet), most people tend to take the maker’s word for it.

Fireworks of this immense size are launched during a show at the Katakai Festival in Ojiya, Niigata Prefecture and are said to have a beautiful blast radius of 800m (2,625 feet). But enough talk. Let’s kick the tires and light some fires watching them in action thanks to a video uploaded to YouTube by Temple Fireworks.

The beginning of the video shows some of the very careful behind-the-scenes preparation for the show as they load the golden wrecking ball into 12m (39 feet) launching pipes. In the tail-end of the video we can watch them actually going off.

Of course not all of the fireworks seen there are Yonshakudama, but they’re big enough that you can eyeball the range of sizes used down to 30cm. Here are what some people who went to the Katakai Festival had to say about it:

“I saw this last year in Katakai. It was interesting watching the entire audience go ‘gya!’ at the shockwave of the explosions! It’s overwhelmingly impressive.”

“I was impressed by the really amazing barrage of fireworks! Tears suddenly started coming out of my eyes for some reason.”

“Katakai’s Yonshakudama unfortunately overdoes it and doesn’t have a pretty shape. Also the fireworks show had bad timing.”

The name “Yonshakudama” uses the traditional measurement of a shaku. The value of a shaku can vary especially depending what you’re measuring, but for building it’s very close to a foot at 30.3333cm. It’s sometimes referred to as a “Japanese foot” in English.

If you want to see a Yonshakudama in person then you can head down to Katakai during festival time, which usually early September.

Source: YouTube – Temple Fireworks via Kotaro Blog (Japanese)