Objectives This study aims to classify the visual discrimination difficulty of Hangul letters for native Japanese speakers and, based on this classification, determine which letters should be prioritized in beginner-level instruction for Japanese learners, thereby providing educational implications. Methods An online survey was conducted with 222 Japanese university students who had no prior experience in learning Korean to examine their visual perception of 19 Hangul consonant letterforms. The assessment utilized a form constancy test, in which participants were required to select the consonant letterforms that best matched a given example. The test was administered in a multiple-choice format with six answer options. Results The overall average number of correct answers among the 222 participants was 9.39, with an overall average accuracy rate of 49.4%. Based on the classification of difficulty levels for each letter, ‘ㅇ, ㅈ’ were categorized as ‘very difficult,’ ‘ㄱ, ㄸ, ㄲ, ㅉ, ㅊ, ㄹ’ as ‘difficult,’ ‘ㅋ, ㅌ, ㅅ, ㅆ, ㄷ, ㅍ, ㅎ’ as ‘moderate,’ and ‘ㅃ, ㅂ, ㅁ, ㄴ’ as ‘easy.’ Conclusions Hangul consonant letterforms with a high recognition accuracy among native Japanese speakers are expected to be easier to recognize visually, thereby reducing the burden in both instruction and learning processes. On the other hand, consonant letterforms with low recognition accuracy are likely to pose greater challenges in visual discrimination for Japanese learners of Korean, highlighting the need for more systematic instruction and targeted learning support. Accordingly, three instructional approaches should be considered: (1) providing explicit instruction on the distinctive characteristics of Hangul letterforms, (2) incorporating diverse typefaces to improve learners’ visual recognition abilities, and (3) integrating letter recognition with writing practice to reinforce learning.