The western half of Tokyo is known to have been a hilly area in feudal times, and there remain a number of slopes, some steep but most not so much. Dorikono-zaka is one such slope in Ota City, the southwestern ward of Tokyo, with a fascinating history.

To begin with, the name is a bit of a mystery, its meaning unclear even to native Japanese speakers. “No” seems to be the common particle indicating possession, similar to “of” in English, but what then could “doriko” possibly be?

Turns out, it’s actually “dorikono,” which still doesn’t make an ounce of sense. Of course it doesn’t; it’s the name of a proto-energy drink that has long been discontinued.

Dorikono, officially spelled Durikono, was a soft drink invented in 1927 by Dr. Kōtarō Takahashi, who was inspired by German physiologist Arnold Durig’s claim that glucose was the most efficient source of energy. Takahashi named his invention Durikono after Durig, himself (Kōtarō), his assistant Nakamura, and three of his other assistants who shared the initial O.

Initially, the energy drink was only served by the doctor to his guests, but word of mouth soon made it a highly sought-after product. It was sold and advertised nationwide by 1930, and even exported abroad as “Drinkall.”

When the Pacific War broke out, however, Dorikono could no longer be produced due to the lack of sugar import. It went back into the market in 1954 but was discontinued in 1970 when Takahashi passed away. His recipe was never made public, making it difficult to bring back the lost drink despite high demands.

The slope in Den’en-Chōfu, Ota City, was given its name in remembrance of Dr. Takahashi, who lived in the neighborhood, and his once-beloved invention.