On March 12, 2016, at an event near Koyo-tei, one of the oldest soba restaurants in Sapporo, temporary tattoos were handed out to foreign tourists visiting the region. But these weren’t any old temporary tattoos. Incorporating traditional Japanese motifs and designs, they were developed in collaboration with a dermatologist to detect soba (buckwheat noodle) allergies.

Buckwheat noodle is one of the most common allergies among kids in Japan, and is well-known throughout the country, with about 0.03 percent of people affected. However, foreign tourists often aren’t familiar with the allergy, which can cause anaphylactic shock just like that experienced by someone having an allergic reaction to peanuts.

So just how do the tattoos detect soba allergies before they become a problem? Visit Spoon & Tamago below to find out!