cross someone's T

English

Blue is crossing Red's T; all of Blue's guns are usable, whilst Red can only reply with their forward guns.

Etymology

From the shape formed by the opposing battle lines, which resembles a capital letter T.

Verb

cross someone's T (third-person singular simple present crosses someone's T, present participle crossing someone's T, simple past and past participle crossed someone's T)

1. (military, nautical) To sail one's battle line across the front of the enemy battle line, allowing one to bring one's full firepower to bear on the enemy battle line while limiting the firepower that the enemy can use in return.
   • 2019 September 18, Drachinifel, 12:24 from the start, in Battle of Tsushima - When the 2nd Pacific Squadron thought it couldn't get any worse...‎^[1], archived from the original on 4 December 2022:

     No sooner has the fleet settled onto this course than a small group of Japanese cruisers and actual, real, live, all-singing, all-dancing, all-features-included, protected-by-the-Emperor torpedo boats begin to move to cross the T of the Russian fleet. Worried about a torpedo attack on his lead battleships and determined to sweep this small formation aside, Rozhestvensky orders his main ships into a line abreast, a far-more-potent display of force that allows every forward-pointing gun on his capital ships to bear at the same time.