Development of Type 4 Chi-To and Type 5 Chi-Ri began before Type 3 Chi-Nu, but there were problems that delayed their combatize. And Chi-Nu was put into practical use first. The reason for this can be seen from the fact that it is numbered “Type 3” which is younger than Type 4 Chi-To and Type 5 Chi-Ri.
Also, Chi-Ri had a problem with its turret, so it is likely that Ho-Ri was able to become a force first.
Therefore, if you are adding Chi-Ri or Chi-To to your game’s development tree, it would be appropriate to place them after Chi-Nu and Ho-Ri.
As a side note, the “Chi” in the Japanese medium tank code name Chi-XX is the initial Chi of Chi-yu-sen-sya (medium-sized tank).
The XX part contains the Japanese syllabary “I-ro-ha-ni-ho-he-to-chi-ri-nu-ru-po”. This code is assigned in the order in which tanks are developed, so the development order will be as follows.
Chi-I (Type-89)
Chi-Ro (Type-95)
Chi-Ha (Type-97)
Chi-Ni (prototype only)
Chi-Ho (prototype only)
Chi-He (Type-1)
Chi-To (Type-4)
Chi-Chi (unknown)
Chi-Ri (Type-5)
Chi-Nu (Type-3)
(Type-95 and Type-97 were classified as heavy and light tanks at the time of development, so it’s strange that they were called “Chi,” but that’s how the people at the time decided.)
Looking only at the code name, Chi-Nu is the last to exist. The Japanese military would have had Chi-To and Chi-Ri before they developed him…or so you might think.
However, in reality, Japan, which was under economic sanctions from the United States and exhausted by the ongoing war, did not have the ability to mass-produce Chi-To and Chi-Ri. Therefore, they hurried to make Chi-Nu, which can be produced at a lower cost, into the military.
A small number of Type 4 Chi-Tos were able to be deployed in combat before the end of the war, but the war ended without them ever seeing combat.
(This is a commemorative photograph of the Type-4 Chi-To and his crew, taken shortly after the end of the war, before it was requisitioned by the US military.
The tank was then taken to Aberdeen Proving Ground, where it was targeted by American artillery fire and destroyed. 
)
Type 5 Chi-Ri had problems with the new 75mm turret, and it was very slow to get it ready for mass production.
They developed a 75mm cannon to counter American and Soviet tanks, but the Soviet Union had already completed the T-34/85, and there were concerns that the 75mm would not be powerful enough. There were various other problems, but all problems were resolved in March 1945.
Ho-Ri is a prototype machine that uses the already completed Chi-Ri chassis and is equipped with a 105mm large-caliber gun, but the gun itself was completed before the Chi-Ri’s turret. As mentioned above, Chi-Ri had difficulty putting its turret into practical use, and its very existence was questioned, so if the war had continued after 1945, Ho-Ri would have been put into action before Chi-Ri.
in historical fact, both were prototypes and no orders were given for mass production.
The president of a Japanese model kit company called Fine Mold talks about what happened at that time, as he actually heard from Type-4 crew members.
The photo above was also owned by an actual Type-4 crew member, and was made public for the first time by the president of Fine Mold, who was given the photo.
(2) 社長が発見！四式中戦車のスクープ写真 発見当時を振り返る 四式中戦車動画2/3【ファインモールドの放談録】 - YouTube
