Research on modality shifts in English-to-Chinese courtroom translation remains limited, despite the critical role of modality in shaping legal nuance, and speaker intentionality in judicial settings. This gap is particularly consequential in high-stakes contexts such as the International Military Tribunal for the Far East (IMTFE), where mistranslations of evaluative judgments could distort historical and legal accountability. To address this, the study explores the translation of modality, a linguistic device used to convey evaluative judgments on assertions or proposals, with a focus on the IMTFE trial records. Using a purposive sampling technique, the study focuses on a parallel corpus comprising authentic English trial records and their corresponding Chinese translations, ensuring a representative dataset that captures the complexity of modality in legal discourse. Adopting a corpus-based approach, the study employs a two-step coding procedure grounded in Systemic Functional Linguistics to analyze modality shifts in terms of modal orientation and value. Quantitative analysis identifies patterns in the distribution and frequency of shifts in the translation. Findings reveal that a small proportion of modality shifts occur, with notable changes in modal value followed by modal orientation. These shifts indicate a departure from the original speakers' modal intentions, particularly in the linguistic strength and manifestation of modal stance in the translated texts. Specifically, the distribution of shifts suggests that the source speakers' intended modal stance becomes weaker and more implicit in the translated texts, primarily due to the loss of high-value and median-value explicit modality. The findings of this study carry implications for translator training, legal translation practice, and institutional frameworks. Future research should explore original Chinese courtroom discourse to compare it with translated discourse, and investigate modality shifts in courtroom translations across diverse language pairs.