The specificity of the military strategy of imperial Japan affected the appearance of the armed forces and the characteristics of various equipment. So, until a certain time, the Japanese army did not have self-propelled artillery installations designed to combat enemy tanks. Attempts were made several times to create such a machine, but all of them, at best, ended with the construction of a small batch of equipment, which, for obvious reasons, could not influence the course of the battles. In addition, the first anti-tank self-propelled guns, created to combat American combat vehicles, were equipped with 75 mm guns, which was not enough to defeat several types of equipment. Thus, the Japanese army needed a new tank destroyer with weapons of at least 80-90 mm caliber.
The understanding of the need for such a technique appeared only towards the end of 1944, when the situation in the Pacific theater of operations did not develop in the most favorable way for Japan and was constantly deteriorating. The United States regularly used the latest tanks, the defeat of which was often an overwhelming task for Japanese tankers and gunners. To change this situation, it was proposed to create a new specialized anti-tank self-propelled gun with a large-caliber gun.
At that time, great hopes were pinned on the new Type 1 105 mm anti-tank gun. This gun was a modified version of the 105-mm anti-aircraft gun, which had previously been developed on the basis of the German FlaK 18. The gun had a 65 caliber rifled barrel (6, 825 m) and was equipped with an automatic wedge breechblock. On tests, the Type 1 gun showed high performance: the initial velocity of the projectile reached 1100 m / s, and the firing range exceeded 20-22 km.
It was the “Type 1” cannon that was decided to be used as the main weapon of the new self-propelled gun, which received the designation “Type 5” or “Ho-Ri” (“Artillery ninth”). In order to simplify and accelerate the development of a promising self-propelled gun was supposed to be made on the basis of the existing project of the medium tank "Type 5" ("Chi-Ri"). However, the base chassis has undergone major changes. In view of the different role of the new machine, it was necessary to change the layout of the internal units of the hull.
According to reports, the hull of the Chi-Ri tank was supposed to be used with minimal changes. Thus, the front of the hull of the ACS "Type 5" was supposed to have a thickness of 75 mm, the sides - 75 mm, the roof - 12 mm. In the aft part, a large wheelhouse was located with a forehead and sides 180 mm thick. Inside the wheelhouse, it was proposed to place the gun and its calculation.
This location of the cabin forced the authors of the project to change the layout of the internal units of the hull. In the front of the hull, a part of the transmission units was placed, behind it was the control compartment with the workplaces of the driver (on the right) and the arrow (on the left). In the middle part of the hull, there was to be a BMW engine with a power of 550 hp. and the rest of the mechanical transmission units. The hull stern was given for the placement of the fighting compartment with weapons and crew.
The chassis of the tank "Type 5" and self-propelled guns "Ho-Ri" had eight road wheels on each side, three supporting rollers, front driving and rear steering wheels. The road wheels were interlocked in pairs and mounted on a Hara-type suspension. The undercarriage was to be equipped with a fine-link caterpillar 600 mm wide.
The Type 5 self-propelled gun was supposed to receive a sufficiently powerful armament complex that would allow it to fight various types of equipment and enemy manpower. The main weapon was the 105 mm Type 1 anti-tank gun. The attachment systems made it possible to aim the gun within a small sector in the vertical and horizontal planes. Rough aiming, as in the case of most self-propelled guns of that time, was to be carried out by turning the entire vehicle.
The 105-mm cannon was seen as a means of destroying enemy tanks and fortifications. In addition, when using fragmentation ammunition, the self-propelled gun could be used to support the infantry. However, the vehicle received an additional weapon in the form of a 37 mm Type 1 cannon. This weapon was located in the control compartment, to the left of the driver. With the help of a 37 mm cannon, it was supposed to destroy light equipment, cars and manpower of the enemy. It should be noted that the additional 37-mm cannon was not an innovation of the Type 5 project, but was borrowed from the Chi-Ri tank.
For self-defense, the promising Type 5 self-propelled guns had to carry one or two rifle-caliber machine guns. According to reports, the mountings for them were to be located on the upper part of the armored wheelhouse.
The new self-propelled gun was built on the basis of a medium tank, which affected its dimensions and weight. The combat weight of the self-propelled guns "Ho-Ri" reached 40 tons. The length of the hull was 6, 5 m, width - 3 m, height - 2, 1 m. The crew of the machine consisted of six people, located in the control compartment and the wheelhouse. The 40-ton vehicle was supposed to reach speeds of up to 40 km / h. The power reserve was estimated at 180 km.
The design of the Type 1 self-propelled gun started no earlier than the last months of 1944, which is why the documentation was prepared only in the spring of 1945. By the end of the summer of 1945, Japanese industry managed to build only one copy of a new combat vehicle. On September 2, on board the American battleship Missouri, the Act of Surrender of Japan was signed, after which all work on military projects ceased.
Due to the end of the war, the Ho-Ri self-propelled guns did not even have time to go to trials. The further fate of the only vehicle of this type is unknown. Probably, it was studied by American specialists, after which it was disposed of. One way or another, the project stopped at an early stage and, by definition, could not have any impact on the course of the war.
It is known that after the completion of the development of the first version of the Ho-Ri ACS, Japanese specialists began work on its new modification. The goal of the project, known as the Ho-Ri II, was to create an anti-tank self-propelled gun based on the Type 5 tank chassis without any major changes in the layout of the internal units. Probably, this project was created with the aim of maximally simplifying the production of new equipment, designed to ensure an acceptable production rate.
The main difference between the Ho-Ri II project and the basic Ho-Ri was the location of the compartments, completely borrowed from the Type 5 (Chi-Ri) medium tank. In the front of the hull, it was proposed to locate a control compartment, behind which there was to be a fighting compartment with a wheelhouse. All units of the power plant were located in the aft engine-transmission compartment. The chassis of the new ACS was borrowed without changes from the base tank. Thus, the self-propelled gun "Ho-Ri II" was actually a tank "Chi-Ri", from which the turret was removed and a wheelhouse with a new gun was installed in its place. The composition of weapons and crew remained the same. The characteristics of the updated self-propelled gun were supposed to remain at the level of the basic "Type 5".
For obvious reasons, the Ho-Ri II self-propelled artillery mount was never built in metal. According to reports, by the time Japan surrendered, part of the design documentation had been prepared and a mock-up of the combat vehicle had been built. The construction of the prototype did not begin.
In the first version of the "Type 5" ("Ho-Ri") project, the influence of German tank building is noticeable. Moreover, outwardly, this self-propelled gun strongly resembled the German Ferdinand combat vehicle. At the same time, its composition of armament is of interest, in which, in addition to the gun and machine gun, a 37 mm caliber cannon was included, which made it possible to hit lightly armored and unprotected targets without spending the main armament ammunition.
The Ho-Ri II project is also interesting from a technical point of view. It is an attempt to simplify the Type 5 ACS as much as possible while preserving all the main characteristics and features of its appearance. From the available information, it follows that the Japanese designers managed to redesign the wheelhouse and the fighting compartment, taking into account the new location. This could help simplify the parallel production of tanks and self-propelled guns based on a common chassis.
Nevertheless, despite the high hopes pinned on the new project, time was playing against it. The development of a new anti-tank self-propelled gun started too late, as a result of which the only prototype built could not even begin testing. If the work started a few months or even years earlier, the Type 5 self-propelled artillery mounts could show their real capabilities in battles with the US Army. However, the Japanese command for a long time underestimated the equipment of this class, which in particular affected the fate of the Ho-Ri project.
