This is “Koma Taisen,” a competition fought between battle tops no more than two centimeters in diameter; there are no other restrictions. Ever since the inaugural 21-team tournament, contestants from small local companies throughout Japan have been putting every last ounce of their design and manufacturing expertise into producing the best possible battle tops. The champion of each tournament is allowed to keep every one of the battle tops in the competition, effectively stealing their competitors’ technology. The tournaments are serious business as the competitors vie for a spot in the upcoming World Championships. This story follows the ups and downs of the designers and creators of these innovative battle tops.