Three-Cornered World, also know as Grass Pillow, is a story of little narrative substance. The main character stays for a time at a country inn. He struggles with the meanings of being an artist and the ability to convey his thoughts and emotions in the written word or on canvas. The innkeeper's daughter is a source of inspiration and intrigue for him.
There are beautiful passages in the story in which Soseki muses about art, and this is the main focus. He published this novel after Botchan. Three-Cornered World is a transition from Botchan to his later meaningful novels. However, in this novel, it seems that Soseki is experimenting with the style and simply letting his thoughts fall onto the paper without trying to organize them in a meaningful way.
I would recommend later Soseki works because starting with this one may leave one underwhelmed by the story.