Drawing of Zhang Xue Yan's war cart, from 'Deng Tan Bi Jiu (《登壇必究》)'.

Zhan Che (戰車) is a type of war cart designed by Zhang Xue Yan (張學顏), Grand Coordinator of Liaodong. Based on an older model by Li Wen Da (李文達), it is designed to be able to keep up with Ye Meng Xiong's lightweight war cart. The war cart is equipped with a leather protective screen, two stacks of rockets and Shen Qiang (神鎗), as well as rows of anti-cavalry spears projecting out of all four sides of the cart.

Xu Lun's line formation, from 'Chou Bian Zuan Yi (《籌邊纂議》)'.

Xu Lun's crescent formation, from 'Chou Bian Zuan Yi (《籌邊纂議》)'.

Xu Lun's raised formation, from 'Chou Bian Zuan Yi (《籌邊纂議》)'.

Xu Lun's wedge formation, from 'Chou Bian Zuan Yi (《籌邊纂議》)'.

Xu Lun's circle formation, from 'Chou Bian Zuan Yi (《籌邊纂議》)'.

Yuan Zhen or circle formation was used when the army was deployed in easily defensible high ground.

Up until this point, I've mostly discussed about various tactics and formations of Ming Southern troops, which focused on small unit tactics to counter the decentralised and extremely unpredictable Wokou. While undoubtedly effective for their intended purpose, Small unit tactics was clearly ill-suited for large scale battle against a serious and more numerous enemy, and should not be taken as being representative of Ming battle tactics as a whole. Ming army faced entirely different circumstances and challenges in the North, and devised entirely different tactics and formations to meet these challenges.


Xu Gong Po Lu Xin Zhen (許公破虜新陣, lit. 'Lord Xu's new barbarian-breaking formation') was a military formation devised by Xu Lun (許論), governor-general of Ji-Liao. Unlike other formations previously discussed in this blog, Xu Lun was not a particularly celebrated or exceptional general (although he did have several victories against the Mongols under his belt), and his formation was also relatively simple and without complicated manoeuvre or exotic equipment. As such, Xu Lun's square formation can serve as a useful baseline for exploring the tactics and formations of other Ming Northern troops.


Organisation
Xu Lun's formation comprised of 3,000 troops (without factoring in command staff, standard bearers, signalers, general's retinues etc.), subdivided into three arms: infantry, cavalry, and support personnels. The organisations of different branches of Xu Lun's formation were as follow:
Infantry

Military unit	Rough modern equivalent	Troop	Support personnel	Total
Zhen (陣)	Regiment	1800/4 Shao	200	2,000
Shao (哨)	Battalion	450/10 Dui	50	500
Dui (隊)	Platoon	15 spear/glaivemen 15 archers 15 handgonners	5	50
Wu (伍)	Team	5	-	5

Cavalry

Military unit	Rough modern equivalent	Troop	Support personnel	Total
Zhong Jun (中軍)	Battalion	900/4 Bu	100	1,000
Bu (部)	Company	225/5 Dui	25	250
Dui (隊)	Platoon	45 cavalry	5	50

Support Personnel (both infantry and cavalry)

Type	Troop
Tang Ma (塘馬)	50 mounted scouts
Tuo Ying (䭾贏)	100 porters (with mules)
Za Chai (雜差)	150 camp followers

Overall

Branch	Troop
Infantry	1,800
Cavalry	900
Support Personnel	300

Equipment
The entirely of Xu Lun's formation was build around one crucial equipment: Ju Ma (拒馬), or cheval de frise. Xu Lun considered Ju Ma to be more convenient, more mobile and deployable everywhere, thus preferable to war carts.

Blueprint of Xu Lun's Ju Ma Qiang, from 'Chou Bian Zuan Yi (《籌邊纂議》)'.

Xu Lun's Ju Ma Qiang (拒馬槍) is relatively small, measuring only six chi five cun or seven chi five cun (208 cm or 240 cm) in width. It is equipped with five spears as well as four wooden props. A chain with a hook, measuring one zhang (320 cm) is installed on the left end of the beam, while an iron ring is installed on the right end. This allows a Ju Ma Qiang to be chained to an adjacent one.

A 45-man platoon guarding three chained Ju Ma Qiang. From 'Chou Bian Zuan Yi (《籌邊纂議》)'.

Every Dui in the formation would be assigned three Ju Ma Qiang. During battle, each Ju Ma Qiang would be guarded by five handgonners standing behind it, while its iron chain would be guarded by five spearmen crouching in front of it, and another five archers standing behind it.

Individual troopers in the formation were given different equipment depending on their roles. Spear/glaivemen were armed with spears, hooked spears, and Zhan Ma Dao (斬馬刀), archers used bows and arrows, as well as quarterstaves (Xu Lun explicitly excluded crossbow), handgonners were armed with handgonnes, most likely Kuai Qiang (快鎗) or Jia Ba Chong (夾把銃). Xu Lun did not specify the equipment for cavalry, although they were probably armed in typical Ming fashion, with bows and arrows and sabres as primary equipment, supplemented by lances, various polearms, maces, quarterstaves, handgonnes, and sometimes rockets.


Formation and Tactics

Xu Lun's square formation, from 'Chou Bian Zuan Yi (《籌邊纂議》)'.

Xu Lun's formation was a gigantic hollow square, occupying an area of roughly 1,648 × 1,648 metre (for comparison, a 3,000-strong early Spanish Tercio could easily fit into a 100 m × 100 m square), with each side composed of alternate one (for cheval de frise) and two (for iron chains) ranks of soldiers. Cavalry were positioned at the centre, forming a secondary "square within the square". The square also had eight "gates", signified by two banners per gate, placed at the middle of each side as well as four corners of the square. These gates allowed the cavalry to move out of the square from any direction to engage the enemy.

During battle, handgonners would be the first to engage the enemy, commencing fire when enemy horsemen entered charging/gallop distance of seventy to eighty paces (114.5 m to 130.8 m). Archers would join the shooting once enemy horsemen came within forty to fifty paces (65.4 m to 81.8 m). If the cavalry charge still did not break, crouching spearmen would wait until the enemy horsemen had losed in to about ten paces (16.35 m) away before suddenly raising their spears in unison. This would spook enemy horses or force the horses to skewer themselves on the spear points before their riders had the chance to react and steer away.

Cavalry acted as the reserve force of Xu Lun's formation, ready to reinforce the line should it be breached, flank the enemy in a pincer attack after they were tied down by the infantry, as well as pursue retreating enemy.


Analysis
It is clear that Xu Lun's formation was designed with one purpose in mind: countering Mongol horsemen, and nothing else. With no vulnerable flanks and rear, hollow square was commonly used by infantry to defend against cavalry. However, by enlarging the square to such a large size, Xu Lun's square also denied large swath of land from the enemy, making it difficult for the enemy to manoeuvre around or bypass the formation.

Thanks to the use of cheval de frise, Xu Lun's formation could stave off cavalry charge with relative ease without having to resort to densely packed pikemen. The large and shallow formation also had the added benefit of being less vulnerable to enemy missiles. On top of that, the formation was large enough to allow the cavalry to immediately mount a countercharge against enemy horsemen that managed to breach the infantry's defence (without ever needing to leave the square), buying time for the infantry to regain cohesion and plug the gap.

Drawing of a Si Chuan Fei Shi, from 'Zhan Shou Quan Shu (《戰守全書》)'.

Si Chuan Fei Shi (四川飛石, lit. 'Sichuanese flying stone') is a type of lightweight, two-man operated traction trebuchet. True to its namesake, the trebuchet was commonly found in Sichuan, although it was also manufactured in Beijing during the twilight years of the Ming Dynasty.

Unlike other Chinese trebuchets, Si Chuan Fei Shi has a A-shaped arm mounted on a single pole, which allows it to be propped on narrow places and change direction easily. This is presumably an adaptation to the mountainous, narrow and uneven terrain of western Sichuan, where many Tu Si (土司, government-sanctioned hereditary chieftain) mountain fortresses are located.