PACOPS Type 89 15cm Cannon

Only 150 of these artillery pieces were made from 1929-1945, however it did take its place as the main gun for IJA heavy artillery units. Classified as a Fortress Gun, it had a firing weight of 10,360kg and could fire a HE or AP shell some 19km (it also could fire shrapnel and illumination shells, however those are not being modeled in this build). It could fire approximately two rounds per minute and had a muzzle velocity of 875m/s.

For this effort I will clone the American 155mm M1A1 gun and edit various parameters in order to mutate it into a plausible weapon for the Japanese forces. For the aper and the bombard ammunition I will use the existing JPN Type 1 HE Shell. Several sources reference that the shell was considerably heavier than that used in other 150mm howitzers; however I have not located a specific reference to the shell weight to make a credible change to the cloned data.

The aper load quantity was zero on the cloned file, and on bombard the load quantity was 80. I am leaving those factors alone for the moment pending additional research. Also needing further research is the accuracy decay at range for the weapon. Absent specific data that I can cross reference I am hesitant to make any change that cannot be supported by credible sources.


This is the general tab where the width, height, length and weight of the unit are adjusted.


This is the performance tab (only data for the aper capability is shown in the screen shot above) where several factors are adjusted from the cloned file, most noticeably the muzzle velocity, caliber and reliability.

The great thing about the Estab Editor is that I can come back and make changes to the data (such as shell weight, accuracy decay at range, etc.) and any estab file using this item will automatically reflect the changes made.

At this point I can build an estab unit for an artillery battalion complete with all sorts of trucks to haul the stuff around, or (what I am doing here at the moment) the creation of a static battery for use in the intended island hopping scenarios.

For this effort I will clone the German BB - HR - 15.5cm K 425 (f) Bty (static) and edit various parameters in order to mutate it into a plausible entrenched artillery piece for the Japanese forces.


When pulling the clone from Germany to Japan, I have to select the appropriate conversion rank for a Hauptmann (equivalent to a captain), in this case that being a Rikugun Taii.


This is the general tab where the rank selection made above is automatically pulled into the Commander Rank field.


This is the Equipment/Supply tab where I remove the German weapons and add in my Japanese weapons. For the moment I am keeping the head count for the battery consistent with the cloned file and will adjust down the road (this can also be modified in the Scenario Editor a number of ways in order to tweak the unit for a specific requirement).

Note the last minute change to the naming convention of the artillery piece from the previous screen shots it was featured in.

The icon tab simply follows the same color scheme as the service level.


This is the Scenario Editor where I add these generic test units to the existing armor test scenario, placing the infantry on the southern airstrip and placing the three static gun units in Mount Tapochau.

Note the updated Saipan map provided by team member Jim Carravallah: it is absolutely gorgeous.


The initial briefing for the test scenario follows a general format I have been using for some time.


Oops!! This is what I get for being lazy and not having created a logical and appropriate Supreme Force yet to cascade all of these test units under. I run back to the Scenario Editor and eliminate the Bn HQ unit, leaving the infantry companies attached to the regimental tank commander.


Standard Reinforcement Schedules exist because I like placing units in the Scenario Editor for intelligence purposes, then removing them to be added to a Standard force list for each side so that I can easily adjust the Min and Max Arrival Strength level settings to affect their initial deployments.

However in this specific test case, because there are now units placed directly into the map, "no reinforcements" is a possible selection (where it was not before when all units came in by way of the reinforcement schedule).


Extra large high quality image of the map is available here.


The Fortress Guns have a Combat Power rating of 4, and I take each under my direct command by ordering one day length artillery barrages against the Marines landing at Red and Green beaches.

I do not like how the name for the unit bleeds over the edge on the left panel, so I will shorten that up for aesthetical purposes.


The artillery is so effective against the Marines that for the first time in running this test scenario my forces (in this case the armor element) is actually able to temporarily take the first objective as the Americans are being pinned on the beach and decimated by 150mm rounds.


By midnight the Fortress Guns are completely out of ammunition for the artillery pieces, and I have lost the Bn HQ as well as 1st and 2nd Coy armor.

After-action Report


A Decisive Defeat outcome is the expected result, however with the added Combat Power of the artillery pieces, the Japanese forces inflicted a significant amount more damage to the Marines than in previous tests that did not contain indirect fire support elements.

Review Final Situation


It will be interesting in some later scenarios to stage an objective (AI based or otherwise) where the static artillery pieces are located as they contain organic infantry that can still fight locally even after the tubes run out of HE ammunition.

1 comment:

  1. Very cool to have fortress guns. Having played the first test scenario I can't believe what a difference these made. I was annihilated by the Marines first go around.

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