Sunagawa carded four birdies and one bogey for a 3-under 69 in Sunday's final round of the 42nd Shinhan Donghae Open, played on the Urban-Links Course (par 72) at Jack Nicklaus Golf Club Korea in Incheon, with total prize money of 1.5 billion won. His 16-under 272 total left him two shots clear of Chang, Moon Do-yeop and Lee Sang-hee, who tied for second at 14 under. It was his first victory since turning professional in 2020, and it came in Korea. The win brought 300 million won in prize money along with a five-year exemption on the Korea Professional Golfers' Association (KPGA) Tour and a two-year exemption on the Japan Golf Tour Organization (JGTO).
The tournament, co-sanctioned by the KPGA Tour and the JGTO with 138 Korean and Japanese players in the field, has now gone to a Japanese player for a third straight year, following Hirata Kensei in 2024 and Higa Kazuki last year. The most recent Korean champion was Ko Gun-taek in 2023.
Sunagawa began the day with a one-shot lead and battled Chang throughout in the same group. When Chang birdied the first and second holes to take a one-stroke lead, Sunagawa answered with back-to-back birdies at the third and fourth to reclaim the top spot. Chang then bogeyed the par-3 eighth, while Sunagawa birdied the par-4 10th and holed a 19-meter birdie putt at the par-4 12th to open a three-shot cushion that all but sealed the win. Chang bogeyed the par-4 14th and birdied the par-5 18th, but it was not enough.
Moon Do-yeop, who is preparing to compete at the 2026 Aichi-Nagoya Asian Games, also shot 6 under to tie for second. He made a double bogey at the par-4 11th after his tee shot found a penalty area, but birdied the 12th and then ran off four straight birdies from the 15th through the 18th to surge up the leaderboard. "The Asian Games start in two weeks," Moon said afterward. "I'll shore up my weaknesses and keep my feel sharp. My putting feels good right now, and if my ball-striking comes around, I think I can post a good result at the Asian Games."
Japan's Ohori Yujiro also chased his first professional victory but had to settle for a runner-up finish. In the sixth grade, Ohori slipped off a jungle gym on a school playground and suffered a serious fracture to his left elbow that required emergency surgery. The injury came not long after he took up golf, and it left him with an aftereffect in which his left elbow bends outward when he grips a club. His fighting spirit in overcoming the impairment struck a deep chord with fans.
