Dear colleagues, I have been collecting unfiltered CCD observations of MASTER OT J144248.29+673944.7 over multiple nights at CBA Extremadura Observatory, using a 0.40-m f/5.1 telescope and SX-46 CCD camera under (mostly) clear skies. The collected light curves did not show obvious periodic modulations, with the exception of last night Dec 10/11, 2021. Regular superhumps with an amplitude of 0.25 mag are clearly visible, establishing MASTER OT J144248.29+673944.7 as a new SU UMa-type dwarf nova. A period analysis using the ANOVA, Lomb-Scargle, Generalized-Lomb-Scargle and PDM methods (Peranso 3.0), yields a combined superhump period of 0.0559 +/- 0.0006d. The object was at mag CV = 15.8 on Dec 11th. I will send my observations to AAVSO, CBA and VSNET for further analysis. Best regards Tonny --- Tonny Vanmunster CBA Belgium Observatory CBA Extremadura Observatory http://www.cbabelgium.com PERANSO : The Light Curve and Period Analysis Software http://www.peranso.com