Before the late Qing Dynasty, the concept of “big knife/Dadao” in the army mostly refers to the knife of the long pole, similar to the shape of the Guandao. The knife with a short handle and a large blade (in popular contemporary Baguazhang culture) is called a single hand knife, it is not called a “big knife”, historically speaking. Ironically the signature instruments used by both disciples of Dong Haichuan are often misinterpreted in Airbending schools of today.
Contrary to popular opinion, the Interlinking/ Weaving routines of Baguazhang as popularized in mainstream and films, contain ‘wrestling with weapons integration’ and not pure empty-hand wrestling. Grappling and takedowns with the instrument in hand, are crucial in feudal melee- often against armed opponents. It is worth noting the forms/drilling methods of Qing-era wrestling are often distinct in aesthetics from the silky/ twisting/ turning style of Swimming Baguazhang.
Dong Haichuan’s Baguazhang footwork shares ancestry with Ming-era systems in Hebei Province, including Bajiquan. The T-step (also called T Square) is well documented in Ming General Yu Dayou’s ‘Sword Classics’, with emphasis on polearms in origin. The reversing T step describes escaping backward, then taking advantage of an arched position in counterstrike. The T method immediately turns the back and attacks the opponent with a square geometry. Treatise: the t-square step can be used for regression, but also for progression; it may retreat; can be advanced in an arc, it can be rotated forward, or it can enter at a curve; Use every possible way to discover and apply the principal.