Sukwang1 is a premium-quality, mid-late maturing cultivar of japonica rice, which was developed to improve resistance to shattering and bacterial blight while maintaining the relatively high grain and eating quality of Sukwang. Derived from a cross between Sukwang and HR29177-AC70-1, the promising line Jeonju662 was evaluated through local adaptability tests (2021-2023) before release. Its average heading date was August 12, with a milled rice yield of 5.66 MT/ha. Sukwang1 exhibited improved resistance to shattering and all four Korean races (K1-K3a) of bacterial blight. Molecular marker analysis revealed the presence of Xa3 and Xa5 for bacterial blight resistance, qFfR1 for bakanae disease resistance, and a loss-of-function allele of qltg3-1 for reduced preharvest sprouting. Target capture sequencing analysis of single-nucleotide polymorphisms revealed 93.6% genetic similarity to Sukwang, indicating that most of the parental background was retained while key agronomic traits were improved. Featuring excellent grain appearance, high head-rice milling recovery, and relatively high taste, Sukwang1 has been designated as a Premium-Quality Rice cultivar by the RDA in 2025, and is recommended for the Honam and Yeongnam plains and southern coastal regions of Republic of Korea (registration number: 10667).