The intermediate breeding material ‘JJ625LG’ was developed to diversify thegrain shape characteristics of Korean japonica rice cultivars. ‘JJ625LG’ was derived from across between ‘HR30198-AC33 (DGS79),’ a japonica breeding material with extra-longand spindle-shaped grains, and ‘Boramchan,’ a high-yielding japonica cultivar with excellentcultivation stability and medium-short and semi-round grains. By employing both bulk andpedigree breeding methods, strong selection pressure was applied to eliminate undesirabletraits inherited from ‘DGS79,’ such as very late heading, long awns, and susceptibility tolodging. Consequently, elite lines with long spindle-shaped grains on a japonica backgroundwere selected. These lines subsequently underwent yield performance and localadaptability tests, during which their agronomic traits were comprehensively evaluated,leading to the final selection of ‘JJ625LG.’ The heading date of ‘JJ625LG’ was August 16th,three days later than that of ‘Nampyeong’. Its culm length was similar to ‘Nampyeong.’‘JJ625LG’ exhibited a higher number of spikelets per panicle, fewer panicles per plant, andheavier 1,000-grain weight than brown rice. Additionally, it showed strong resistance tobacterial blight (races K1, K2, and K3) but was susceptible to viral diseases and insectpests, indicating the need for further improvement in these areas. Its grain yield was comparableto that of ‘Nampyeong.’ With a brown rice grain length of 6.34 mm, ‘JJ625LG’ wasclassified as a long-grain type and had a grain length-to-width ratio of 2.64, reflecting aspindle-shaped morphology. It carried the GW2-gs3-qSW5 allele combination associatedwith grain shape, which is a genetic profile not found in existing Korean japonica cultivars. Although its milling recovery rate was similar to that of ‘Nampyeong,’ the presence of manybroken rice due to its long grain shape resulted in a lower percentage of head rice. The eatingquality of ‘JJ625LG’ was excellent, with its grains exhibiting the sticky and soft texturetypical of japonica rice and receiving high scores in sensory evaluation. As the first intermediatebreeding material in Korea with long and spindle-shaped grains in a japonicabackground, ‘JJ625LG’ is expected to contribute significantly to diversifying the traditionallynarrow grain shape spectrum of Korean japonica rice cultivars (Registration No. 10166).