Great Ming Military

The name Bai Gan Bing originally referred to various groups of white shafted spearmen from the general region of Southwest China (including Sichuan, Guizhou and Chongqing but excluding Yunnan and Tibet). However, after Qin Liang Yu's rose to prominence, it became almost exclusively associated with ethnic minority troops from Shizu that served under her. These Shizu troops were actually raised and co-led by both Qin Liang Yu and her husband Ma Qian Cheng (馬千乘), then Tusi of Shizhu, until Ma Qian Chen's untimely death forced her to become the acting Tu Si of Shizhu and sole commander of the unit.

Equipment

Bai Gan Bing famously wielded pikes with white coloured shafts known as Bai Gan Zi (白桿子, lit. 'White shaft'), from which they derived their name. They also used bamboo pikes, Lang Xian (狼筅), glaives, swords and sabres. Bai Gan Bing did not use bows and arrows, but used crossbows occasionally.  

For defensive equipment, they wore cotton armours or blankets on top of iron armours. Some Bai Gan Bing also carried rattan shields.

Orgainsation and tactics

As Bai Gan Bing was a military unit comprised of kinsmen and led by a chieftain, it was only natural that many Qin Liang Yu's family members, including her siblings, sons and in-laws, also served leadership roles in the unit. Bai Gan Bing also included five to eight hundred warrior monks known as Luo Han Bing (羅漢兵, lit. 'Arhat troop') and some female troops among their ranks.

Very little is known about the tactics of Bai Gan Bing. It appears that they preferred to fight in large pike formation, and had little in the way of ranged weapon. This was in stark contrast to troops from Zhejiang that preferred smaller but versatile mixed-unit formation (i.e. Mandarin Duck Formation), and made heavy use of firearms.

Mountaineer extraordinaire
Sichuan troops were renowned for their hardiness, bravery, ferocity in battle, ability to navigate dangerous terrain, as well as their expertise in the usage of pike, Lang Xian, and sword. While technically part of Chongqing instead of Sichuan, Bai Gan Bing of Shizu shared much of the same reputation as their Sichuan neighbours. Add to this the fact that they were well-drilled and well-disciplined under the leadership of Qin Liang Yu, and it's obvious why their name was feared far and wide.

Qin Liang Yu's troops first made themselves known during the war of Bozhou, in which Qin Liang Yu and her husband rapidly defeated seven strongholds of rebellious Miao people with just three thousand and five hundred troops.

Their second major battle, the Battle of Hun River, was ironically both their finest hour and their worst defeat. During the battle a four thousand strong Sichuan force (along with three thousand Zhejiang artillerymen that deployed separately and were unable to come to their aid) was able to inflict heavy casualties on a mounted Manchu force several times their size, only to be blasted to smithereens by turncoat Ming artillery.

Despite the defeat, Bai Gan Bing did not perish and continued to resist rebels and Manchus alike in Shizhu. In fact, they even outlasted Ming Dynasty itself, surviving well into the reign of third Qing emperor.



Reference
Blog post updated with new and more accurate information taken from 白桿兵 on 逸佚居 (Traditional Chinese).