mutual attack training
Martial arts term for a training method where partners take turns attacking each other, often used in kendo and other disciplines. Compare 相懸かり (sense 2).
See also: 相掛かり
In kendo practice, we do striking drills through mutual attack training.
相懸かり is a broader term for mutual attack or simultaneous offense; 相懸かり稽古 specifically refers to the training exercise based on that concept.
Compound of 相 (mutual), 懸かり (attacking, from 懸かる), and 稽古 (training, practice).