unmask one's batteries

present singular third person unmasks one's batteries · participle present unmasking one's batteries · participle past unmasked one's batteries · past unmasked one's batteries

1. datedidiomaticTo begin a decisive action, especially one that reveals one’s true strength or character.

   Meanwhile the Germans had shown that they themselves were not yet ready to unmask their batteries.

   1956, Carlile Aylmer Macartney, October Fifteenth: A History of Modern Hungary, 1929–1945, volume 1, page 169

   3 more examples

   “Your father is fond of surprises, as you must have seen,” Cuthbert rejoined. “He won’t unmask his batteries till all is ready for action.”

   1858, William Harrison Ainsworth, Mervyn Clitheroe, volume 2, page 278

   The bishops, proud of this first victory, believed that a second would be easily won, and they unmasked their batteries.

   1877, J. H. Merle d’Aubigné, translated by William L. R. Cates, History of the Reformation in Europe in the Time of Calvin, volume 7, pages 198–99

   The Evénément^([sic]) remarks:—“The Egyptian Question is not a French or an Anglo-French, but a European question, and the spoliation just perpetrated by England, has enlightened Europe in time. It is not wise to unmask one’s batteries too soon.”

   1882 August 26, Public Opinion, volume 42, number 1,092, page 262

2. Used other than figuratively or idiomatically: see unmask, battery.