Portrayal of the Physician Hua Da Scraping the Bone of Guan Yu to Treat an Arrow Wound (Hua Da hone o kezurite Guan Yu ya-kizu o ryoji suru zu), Utagawa Kuniyoshi, 1853
"Guan Yu was once injured in the left arm by a stray arrow which pierced through his arm. Although the wound healed, he still experienced pain in the bone whenever there was a heavy downpour. A physician told him, "The arrowhead had poison on it and the poison had seeped into the bone. The way to get rid of this problem is to cut open your arm and scrape away the poison in your bone." Guan Yu then stretched out his arm and asked the physician to heal him. He then invited his subordinates to dine with him while the surgery was being performed. Blood flowed from his arm into a container below. Throughout the operation, Guan Yu feasted, consumed alcohol and chatted with his men as though nothing had happened." (Wikipedia)
This is such a famous story, and probably true to a degree. However, there is no mention of Guan Yu playing Go in the original text from Records of the Three Kingdoms (三國志 is a historical book, written in the late 3rd century AD, just decades after this said event happened), and it didn't even specific who was the doctor, just said he was still drinking and eating like nothing. The more vivid descriptions came from the 14th century novelization of the Three Kingdoms - Romance of the Three Kingdoms (三國演義), which was more than a thousand years later.
There are a lot of depictions of this event, since Guan Yu had since raised to the status of divinity in Chinese fork religions, and we can see many art, murals, and wall statues about Guan Yu in his temples or related temples.