Let's take the 685th Regiment of the 343rd Brigade of Lin Biao's 115th Division in 1937 when the Eighth Route Army had just completed its reorganization, which was reorganized from the Red 2nd Division of the Red First Army with outstanding combat achievements. Famous founding lieutenant general.
Therefore, it is obvious that the 685th Regiment was composed of regimental subordinate units and three infantry battalions, which was in line with the formation principle of the "three three systems" of the National Revolutionary Army at that time. However, because the Red 2nd Division was the main force of the Red Army, it was composed of 12 infantry companies when it was reduced to a regimental structure. That is to say, when the 685th Regiment of the Eighth Route Army crossed the Yellow River in the east to the anti-Japanese front, each battalion had four infantry companies (and another battalion belonged to a heavy machine gun platoon), and each battalion had more than 600 troops.
At the beginning of the founding of the Whampoa Army, the National Revolutionary Army was Soviet-style equipment, Soviet-style training and Soviet-style organization, so it also followed the principle of "three three systems" of the Soviet army. Basically, the division administered three regiments, the regiment administered three battalions, and the battalion had three companies, and this principle was also followed when it was expanded into the First Army, and Commander He Yingqin was qian Dajun, commander of the 1st Division, Liu Zhi, commander of the 2nd Division, and Tan Shuqing, commander of the 3rd Division. The corps later grew to nine divisions, but was soon split into three corps: the 1st, 9th, and 32nd.
However, during the Northern Expedition, due to the rapid expansion of the National Revolutionary Army, the formation and training gradually transitioned from division to "division morality", coupled with the recruitment and rebellion of warlord troops during the period, the military system was once very chaotic, and the "brigade level" number began to appear. In 1929, when it was sorted out, it was roughly divided into the "A-type Division" of the Three Brigades and Six Regiments, the "B-Type Division" of the Second Brigade and the Fourth Regiment, and the "C-Type Division" of the Three Regiments directly under his direct jurisdiction, because Lao Chiang had never really completed the unification of "military government and military orders", so the organization of the Central Army, the Miscellaneous Army, and the local armed forces was a mess.
However, below the regimental headquarters, at that time, there were basically only two types of "three-three system" and "four-four system", that is, three battalions or four battalions under the jurisdiction of the regiment, and no more or less was a special case. For example, Song Ziwen's Tax Police Corps is under the jurisdiction of each regiment with three battalions, but each battalion has four infantry companies and seven special forces companies, with a regimental strength of more than 5,000 people, while the normal infantry regiment has a strength of between 1,500 and 2,500 people (depending on the fullness of soldiers).
After the end of the Central Plains War, the Nanjing Military and Political Department finally had the conditions to start the unified organization of the national army, and put forward a plan to first complete 60 "adjustment divisions" and then gradually implement the other divisions. Both the Central Military Academy's Teaching Corps and the adjustment divisions of each period have implemented the principle of "three battalions under the jurisdiction of the regiment", and then each battalion has three infantry companies and one machine gun company.
Of course, before this rectification was completely completed, the War of Resistance Against Japan broke out, but the principle of the three-three system of the division's second brigade and the fourth regiment and below the regiment was indeed the standard establishment at that time. So you see that when the Eighth Route Army first completed its reorganization, the 115th, 120th, and 129th Divisions also basically followed this principle of organization, because the Nanjing Military and Political Department wanted to verify your basic organization, and if you wanted to make minor adjustments, you could only make minor adjustments in the sub-battalion structure.
After the Battle of Wuhan, the "brigade" level was abolished, and the divisions became three regiments directly under the direct jurisdiction (the Yanshi Division also had a field supplementary regiment without a number), which was to say, it was better to find out in actual combat whether the "Triangular Division" was more conducive to command. Therefore, in the middle and late period of the War of Resistance Against Japanese Aggression, the standard troop establishment returned to the state of the "three-three system," that is, the general standard system of the group army under the jurisdiction of three corps (or two), the three divisions under the jurisdiction of the army (or two), the division under the jurisdiction of the three regiments, and the three battalions under the jurisdiction of the regiment.
During the Liberation War, there was not much difference, and the armies of the Kuomintang and the Communists were still the basic organization principle of the "three-three system" below the division level, for example, after the 74th Army was reduced to the integrated 74th Division, the three divisions under its jurisdiction were renamed the Integrated Brigade, and the three infantry regiments below the brigade (three new regiments were not rebuilt during the Battle of Menglianggu, but the numbers were all given), and this was even more true below the regiment. In combat, both offensive and defensive, each infantry regiment was customarily deployed with two battalions in the first line, while the regimental headquarters held the other battalion as a reserve.
As for the establishment of the Eighth Route Army after 1938, there is no need to refer to and interpret too much, because the Eighth Route Army is in a period of great development behind enemy lines in North China, and it is impossible to openly apply to the Chongqing government for a new designation, so the establishment is completely controlled by the Headquarters of the Eighth Route Army (18 episodes) on its own, and it must also be adjusted according to the actual needs of combat behind enemy lines. For example, during the most difficult period from 1941 to 1942, it was divided into large regiments and small regiments, and the small regiments only had five infantry companies, and the battalion-level structure was simply abolished. Therefore, we must pay attention not to study military history with the establishment of the Eighth Route Army, which belongs to the special situation of a special period.
It is not impossible that Li Yunlong's independent regiment in "Bright Sword" can develop to eight battalions; "letting go of the masses and letting go of the expansion of the armed forces" is a slogan, but such a structure cannot exist for a long time, and it must be noted that the Eighth Route Army has its own organization of "units below the brigade level", and if it really develops to seven battalions, it will soon be split into new regimental units; otherwise, how did the 46 regiments dispatched by the 129th Division come from during the Hundred Regiments War?
You know, when the 129th Division was first established, there were only four regiments of the 385th and 386th Brigades (the other division directly instructed the regiment), so it was inevitable that the troops would be newly built and split and reorganized, and by the time of the victory of the War of Resistance, the Jinji-Hebei Luyu Military Region, which was also the 129th Division, already had 300,000 troops, so how many regiments would be needed?