Talk about military affairs | Japan follows suit and develops a new 155 mm truck gun, and plans to deploy southwest outlying islands.
Recently, the Japanese Ground Self-Defense Force demonstrated a new type of 155 mm truck gun under development. As the latest 155 mm truck gun, what is the significance of the gun for the future development of the Japanese Ground Self-Defense Force? What are the advantages and disadvantages of the gun design?
Follow suit: the development history of Japanese large-caliber artillery
In the development and equipment of large caliber artillery, the Japanese Ground Self-Defense Force has taken the development mode of paying equal attention to self-research and introduction and following European and American countries from the beginning. Initially, the Japanese Ground Self-Defense Force was equipped with M52 105mm self-propelled howitzer and M44 155mm self-propelled howitzer provided by the United States. These two types of artillery belong to the first generation of large-caliber self-propelled artillery developed by the United States after World War II. Although their overall performance has been improved compared with similar artillery in World War II, they still adopt the open combat cabin design, and their protection ability is weak. Therefore, since the 1960s, the Japanese Ground Self-Defense Force has independently developed 74-type 105mm self-propelled howitzers and 75-type 155mm self-propelled howitzers. The overall design of these two types of guns refers to similar equipment in Europe and America. Especially the 75-type 155mm self-propelled howitzer, the overall design layout is almost the same as that of M109-type 155mm self-propelled howitzer in the United States.
Since then, the Japanese Ground Self-Defense Force has introduced the M110 203mm self-propelled howitzer from the United States. In this way, the 74-type 105mm self-propelled howitzer and the 75-type 155mm self-propelled howitzer independently developed by Japan, together with the American M110-type 203mm self-propelled howitzer, became the main large-caliber barrel guns of the Japanese Ground Self-Defense Force in the 1970s and 1990s. However, because the four islands in Japan are mountainous, Shikoku Island has the largest mountainous area, accounting for 80% of the total area. Even the relatively flat Hokkaido Island is nearly half mountainous. Therefore, the Japanese Ground Self-Defense Force can only deploy all heavy equipment such as main battle tanks and large-caliber self-propelled artillery on Hokkaido Island.

The Japanese Ground Self-Defense Force demonstrated a new type of 155 mm truck gun under development.
In this way, the Japanese Ground Self-Defense Forces in the south of Honshu Island are relatively short of large-caliber artillery equipment. Therefore, in 1983, Japan obtained the franchise of FH-70 155 mm self-propelled howitzer from Sweden. At present, all 492 FH-70 155 mm self-propelled howitzers in active service of the Japanese Ground Self-Defense Force are deployed in the south of Honshu Island. The gun needs to be towed by a military truck for long-distance maneuvering, and can rely on the power device equipped on its own gun mount for entering and leaving the position or for short-distance maneuvering. Therefore, the equipment of the gun has greatly improved the combat capability of the Japanese Ground Self-Defense Force in the south of Honshu Island.
Since then, European and American countries have set off a wave of developing 52 times 155 mm howitzers. As a result, Japan also "followed the crowd" and began to develop the second generation of 155 mm self-propelled howitzers in 1992, namely the 99-type 155 mm self-propelled howitzers. The overall layout of the gun refers to the famous PzH2000 155 mm self-propelled howitzer in Germany, especially the turret and barrel design, which is almost the same as the latter. However, because the Japanese Ground Self-Defense Force did not demand heavy armor, the total combat weight of the 99-type 155 mm self-propelled howitzer was 15 tons lighter than that of the German PzH2000 155 mm self-propelled howitzer, but it still reached 40 tons. From the overall performance, the 99-type 155 mm self-propelled howitzer does not have much brilliance compared with similar guns in other countries. It is only because the quantity of this type of artillery equipment is pitifully small, which is less than a fraction of the purchase quantity of some similar models in other countries, so it has also created a unit price record of up to 8 million US dollars.
After the troops in the area north of Honshu Island completed the replacement of the 75-type 155mm self-propelled howitzer with the 99-type 155mm self-propelled howitzer, the Japanese Ground Self-Defense Force began to consider developing a new 155mm self-propelled howitzer for the troops in the area south of Honshu Island to replace the FH-70 155mm self-propelled howitzer that has been in service for more than 20 years. This is the new 155 mm truck gun we see today.

The 75-type 155 mm crawler-type self-propelled howitzer previously equipped by the Japanese Ground Self-Defense Force
German-Japanese hybrid: Japanese truck guns use German trucks.
France’s "Caesar", the world’s first 52 times 155 mm truck gun, was publicly unveiled as early as 1994. Since then, many countries in the world have begun to develop their own large-caliber truck guns with reference to the overall design idea of French Caesar, including Russia, Sweden, Israel and other military and industrial powers, as well as developing countries such as Iran, Vietnam and India. This also shows to some extent that the research and development threshold of large-caliber truck guns is actually not very high. It was not until 2012 that Japan began to develop 52 times 155 mm truck guns, which was a bit "hindsight".
Similar to the large-caliber self-propelled gun designed and developed in Japan before, the overall design layout of this new 155mm truck gun also has a reference template, that is, the second-generation Caesar 155mm truck gun introduced by French Ultraman Company. Although the first generation "Caesar" 155 mm truck gun pioneered a new type of weapon and equipment, it also has many shortcomings, such as limited chassis bearing capacity, poor shooting stability, low degree of automation, and no armor protection. To this end, the French company Ultraman improved and developed the second generation "Caesar" 155mm truck gun.

Type 99 155 mm self-propelled howitzer is known as the most expensive self-propelled howitzer in the world, and the unit price is as high as 8 million US dollars.
The chassis of the second generation "Caesar" 155 mm truck gun was changed from the first generation Renault 6×6 military truck to the Czech Tetora 8×8 heavy truck. This 8×8 heavy truck chassis has better off-road performance and stronger bearing capacity. Although the total combat weight of the second-generation "Caesar" 155 mm truck gun has soared from 17 tons of the first generation to 30 tons after replacing the chassis, it can still meet the requirements of being carried by A-400M large transport aircraft. Similarly, Japan’s new 155 mm truck gun also uses the 110 HX81 8×8 heavy truck of German Mann Company as the bearing chassis, and the total combat weight is also about 30 tons, and the Japanese C-2 new transport aircraft can also carry it.
Japan’s new 155 mm truck gun is 11.4 meters long, 2.5 meters wide and 3.4 meters high. There are five gun crew members, three of whom are in the cockpit, and the other two are sitting in the semi-closed crew cabin at the back of the engine compartment. The conditions are relatively harsh. The firepower of this type of gun is basically the same as that of the 99-type 155 mm self-propelled howitzer, including the bolt, the recoil mechanism, the recoil mechanism and the barrel, but it has been improved according to the layout requirements of the truck gun. Judging from the installation position of the gun, the position of the bolt is still relatively high after the barrel is erected. Therefore, the design of the large-scale hydraulic parking hoe of Japan’s new 155 mm truck gun is similar to that of the second generation "Caesar" 155 mm truck gun, and there is also a platform for people to get up and down. However, the ammunition box on the side of Japan’s new 155 mm truck gun has a low height, so there is no folding pedal like the second generation Caesar 155 mm truck gun.
At present, the Japanese Defense Ministry has not disclosed much about the specific performance parameters of the new 155 mm truck gun. Therefore, it is difficult to judge how the performance of this gun compares with other similar models. However, from the overall layout, Japan’s new 155 mm truck gun is obviously the result of many factors. For example, from the choice of chassis, Japan has a developed automobile industry, and domestic enterprises are fully capable of providing similar 8×8 heavy trucks, but they use the German company 110 HX81 8×8 heavy trucks with relatively low cost but not inferior performance.

In order to control the cost, Japan’s new 155 mm truck gun has to relax other performance requirements, such as maneuverability, off-road, protection and personnel comfort.
However, considering that this new 155mm truck gun is going to replace the 492 FH-70 155mm self-propelled howitzers currently in service in Japan’s Ground Self-Defense Force, its purchasing unit price must be controlled at a low level, and it must not be as high as the 99 155mm self-propelled howitzers. Otherwise, even if it is not a one-on-one replacement, the Japanese Defense Ministry can’t afford it at all. It is for this reason that the Japanese Steel Works, the developer of the new 155mm truck gun, will choose the German Mann 110 HX81 8×8 heavy truck for both military and civilian use, instead of the military 8×8 heavy truck developed by domestic enterprises.
Of course, while controlling the cost, Japan’s new 155 mm truck gun has to relax other performance requirements, such as maneuverability, off-road, protection and personnel comfort. Therefore, we can see that Japan’s new 155 mm truck gun is equipped with a protective steel plate at the top of the cockpit to resist the muzzle shock wave, and the two gun crew members can only stay in the canvas tent full of noise and vibration. Moreover, the minimum launching elevation and directional firing boundary of this type of gun will also be affected to some extent. It is said that during the trial period of this type of artillery’s multi-door sample guns in Fuji School (a comprehensive military school where Japanese Ground Self-Defense Forces train officers below infantry, artillery and tank corps), the defects of poor shooting stability were exposed, and it was even necessary to install lateral hydraulic hoes to enhance stability. Therefore, this type of artillery must undergo at least several rounds of design improvements to meet the requirements of the Japanese Ground Self-Defense Force.

The new 155 mm truck gun is mainly used to replace the 492 FH-70 155 mm self-propelled howitzer currently in service in Japan’s Ground Self-Defense Force.
Maneuver and Firepower: Lu Zi steadily improves southwest combat capability.
The launch of this new type of 155mm truck gun actually continues the development path of the Japanese Ground Self-Defense Force to continuously enhance the combat capability in the area south of Honshu Island, the so-called southwest area, since the 21st century. In the past ten years, Japan’s Ground Self-Defense Force has continuously purchased and equipped a new generation of main battle equipment suitable for the operational requirements in southwest China, such as the 10-type main battle tank called "the first fourth-generation main battle tank" by some people and the 16-type 105 mm wheeled assault gun. Type 10 main battle tank mainly replaces the old Type 74 main battle tank and becomes the main armored main battle equipment of Japanese Ground Self-Defense Force in southwest China. The 16-type 105 mm wheeled assault gun can take on the task of direct fire support for highly mobile troops with its excellent maneuverability and firepower.
The new 155 mm truck gun will gradually replace the old FH-70 155 mm self-propelled howitzer, which will further strengthen the maneuverability of the artillery unit of the Japanese Ground Self-Defense Force. In particular, the new 155 mm truck gun has air transport maneuverability, and the Japanese Ground Self-Defense Force can quickly deploy the gun to other important islands other than the four local islands, such as Okinawa and Miyako. In this way, the new 155 mm truck gun with long-range precision guided artillery shells will also become the main equipment of the artillery unit of the Japanese Ground Self-Defense Force to attack the sea, and together with the shore-to-ship missiles, it will form the main battle force to block the strait.