Speaking half-apologetically, the estate agent mentioned that the house was beside an ankyo. Hideo Takayama and his fiancée were inspecting what might become their future home in Ikenoue, Setagaya-ku, and it was the first time they had encountered the term. 渠 (an) denotes a ditch or canal, while 暗 (kyo) signifies darkness or disappearance. Combined, they form ankyo (暗渠), which translates directly to dark canal. This somewhat eerie word refers to a waterway that has been covered and built over—a concealed stream or river. Depending on one's perspective, a local ankyo is not always viewed as an attractive property feature.

Several years passed before Takayama's marriage ended. He vacated his ankyo home and settled into a modest apartment alone. Nowadays, he is interviewed across various media with some regularity, and each time, he reflects on his origin story, including the transitional period following his divorce. It was a time of emotional lightness and freedom from his previous life. Yet, it was equally defined by a search for direction, spending his days ambling through the city on a well-worn bicycle.

From his new neighbourhood, a web of narrow paths connected areas such as Sakura-Shinmachi, Toritsu-Daigaku, and Sangenjaya—a collection of refined locales served by the south-westerly Den-en-toshi and Tōyoko train lines. Drawn to these backstreets, Takayama researched their origins and discovered that they had been constructed over old riverbeds, marking his second encounter with ankyo. He found that the paths mirrored the meandering courses of their original waterways, naturally threading through valleys and avoiding steep inclines. Quiet, convenient and free of cars, these discreet shortcuts between destinations were perfect for casual cycling.