Essayist and artist Nancy Seki died Wednesday at the age of 39, her management office said.
Seki died at 12:47 a.m. in a hospital in Tokyo shortly after falling ill in a taxi as she returned home from dinner with friends Tuesday evening, it said.
The cause of Seki's death has yet to be determined, the office said.
Seki, whose real given name was Naomi, was a native of Aomori city. She wrote sarcastic and witty essays, particularly about TV shows and entertainers, in several magazines.
In addition to her essays, Seki became known for caricatures produced by carving images on erasers.
Seki began her career as an illustrator after quitting studies at Hosei University in Tokyo.