<![CDATA[Contemporary formal theatre arts education tends to focus on conventional techniques and rigid scripts, which significantly limit students' exploration, creativity, and spontaneity at the secondary school level. Consequently, students' self-confidence and self-expression are often sub-optimally developed. This study aims to develop and validate structured improvisation techniques within the theatre arts curriculum to enhance students' self-expression, employing a Research and Development (R&D) approach with a case study location at a private Christian Junior High School (SMPK Swasta) in Jakarta. Qualitative methods, including participatory observation and in-depth interviews, were utilized, with data analysis conducted through the Miles & Huberman model. The intervention focused on the "Practice – Express – Reflect – Revise" Cycle Model, integrating Spolin's Theater Games with local Ketoprak wisdom adaptations: the "Kata Berkait" (Chain Word) and "Udar Rasa" (Airing of Emotion) techniques. Findings indicate that the structured implementation of improvisation techniques successfully enhanced students' verbal and non-verbal expression, spontaneity, and self-confidence significantly. This reflective learning model proved effective in overcoming performative anxiety and curricular rigidity, serving as a vital "expression laboratory" for 21st-century soft skill development. It is recommended that improvisation be integrated as a core component of the theatre arts curriculum to foster a more authentic and empowering learning experience.]]>
