Japan '46 Operation Coronet Allied AAR

[ComradeP]

14th of March 1946 14:00 Turn 136



XIII (Armored) Corps blew a hole in the Japanese line, but the terrain and weather conditions make any kind of exploitation into the Japanese rear impossible. Still, the main goal was to remove the Japanese from 24th ID's flank and that's working. Secondary goal would be to knock out some of the coastal guns in their bunkers.

A Pershing unit has been firing at the guns in a bunker at the 100 point objective west of Oshikiri for most of the game, knocking one out through direct fire. 



I moved one of XXIV Corps' engineer battalions south to clear the remaining obstacles along the coastal primary road from Mobara to Matsusaki together with 7th ID's engineer battalion. The motorized elements of the division are moving back north, the infantry will follow soon.






The 6th Marine Division is nearly in position north of Katakai.

[ComradeP]

15th of March 1946 Soft conditions 04:00 Turn 141



Japanese losses from direct fire from tank stacks USAAF bombing runs are stiff, but progress isn't spectacular.

Carpet bombing runs did knock out some artillery stacks as they were forced to withdraw.



There's only 1 Japanese unit left in the Boso Peninsula, an observer at Susaki west of Tateyama






6th Marine Division starts its push north. The idea is to hit the Japanese units in the Field hexes hard with naval artillery and slowly roll north along the coast. Meanwhile, XXIV Corps will strike north from its position at Honno. 4th Marine Division will slowly move towards the coast as well, leaving only 1st Marine Division in place to help XXIV Corps until the division is relieved by reinforcements about to arrive.

[ComradeP]

15th of March 1946 14:00 Turn 146



The coastal battery at Zemba has been knocked out and the bunker it was in now contains US forces. The bunker at Sanya has been vacated.



7th ID moves north, the Boso Peninsula is secure.



As predicted, Japanese losses from naval artillery were stiff. The attack by the 6th Marine Division is spearheaded by armoured units. I'm trying to keep the Marine battalions out of line of sight, as Japanese artillery can be just as painful as my naval artillery on the Field hexes.

You can place two divisions through a strategy choice: the 97th ID (arrives 15th of March) and and the 11th Airborne Division (arrives 18th of March). Both divisions can land in either the First or Eight Army beaches or a special location.

97th ID can launch an amphibious invasion if the Izu Islands (nice for flavour, but the division would then end up being out of play for the rest of the game after capturing the island) or an amphibious invasion of South Lamour Beach (south of Yokosuka) which is an interesting option, but I fear it would be a suicidal one in my case.

I decided to land the 97th ID on the Marine beaches. They'll move towards the woods north of Honno to aid the XXIV Corps assault and relieve the 1st Marine Division.

11th Airborne can make airborne landings west or east of Tokyo, but that's also too risky for my liking. I haven't decided where I want to commit the Airborne forces yet.

Choosing a landing on one of the initial invasion beaches makes the units land intact without Invasion losses.

[ComradeP]

I'll fill in the missing turn commentary on Sunday.

[MarathonMan]

Looks absolutely brutal, definitely captures the slog that such an operation would've been.

[ComradeP]

It's both frustrating and highly entertaining at the same time by now, if you can handle the mostly positional warfare.

The campaign has issues though, which I'll describe in the AAR.

[MarathonMan]

I read your Japan 45 aar; do the issues have anything to do with unit balancing? The Japanese definitely seemed to have the deck stacked in their favor in that case.

[ComradeP]

Considering the Japan '45 campaign I wrote the AAR for stopped shortly after it was started, it's hard to tell how things would have ended up in detail but some issues were already visible.

Japan '45 and Japan '46 share many unit stats, but the differences between the campaigns also make the issues different.

There are system/mechanic related issues, scenario issues in terms of the values/schedules used and balance issues caused by the actual plans (which the designer can't really do anything about).

In the case of Olympic, none of the corps can support the corps at other beaches and one of the landings is extremely exposed to Japanese counterattacks. Weather conditions also make promises of constant air support unrealistic.

In the case of Coronet, the follow-up corps only arrive after a month aside from XIII Armored Corps, possibly due to logistics. Japanese reinforcements arrive within days.

I might as well discuss other balance issues here, aside from unit stats which I'll post later.



There are two values in the parameter data dialogue that stand out: the first one is the Japanese recovery rate of 2%, which combined with an overall higher unit quality (effective rate is 3% for B quality units) and plenty of units to hold a line make it more difficult to inflict long term losses through attrition.

The second are the breakdown rates. The campaign features mediocre to poor weather conditions in March and high movement cost terrain for tracked units. Pershings also have Low Reliability. The Allied breakdown rate of 8 means I'm losing a vehicle when moving 1 or 2 hexes in difficult terrain quite often.

That would be less of an issue if US Army tank battalions were not composed of 3 different tank types, the Chaffee, the Sherman and the Pershing, which make loss recovery less efficient as bigger units equals quicker more replacements as the maximum unit size is used as a base when calculating replacements. You also can't combine and breakdown all units in the battalion in case one unit regains strength more quickly or is full strength whilst others are not.

Breakdown losses combined with excellent Japanese AT values can quickly knock a tank battalion down a size if left at the frontline. Not entirely unrealistic, but the rate feels excessive. That's also why I prefer to keep tanks other than the Pershings out of reach of Japanese infantry aside from the cavalry units that don't have a range 1 hard attack.

Tank tactics for the Marines are slightly different as they don't have 76mm equipped Shermans and thus don't have a range 2 hard attack. That means I need to watch out for Japanese medium tanks and SPAT units as well.

Breakdown rates are also fairly harsh for the Japanese, but they have A and B quality tank units which reduce breakdown rates. Thus far, they've also been closer to roads.

As for the release schedule: the designer, in both the "narrative" he wrote for the campaign and the scenarios with later start dates assumes a very limited number of Japanese reinforcements will move to the beaches. In reality, most units can start to move towards the invasion beaches within days.

On the 12th of March, every single Japanese unit is released, including all the irregular/militia units in Tokyo. By that point, most of the other divisions are already at the front. You're facing a serious numerical disadvantage as the Americans, which is particularly difficult to overcome in the Eighth Army sector.

As Elxaime, my opponent, also posted in another thread, the Japanese command structure isn't very flexible due to the way the reattachment mechanic works: units assigned to a corps HQ can be reassigned, but not units above that level and the majority of the Japanese units are assigned to an Army-level HQ. That means units belonging to a certain army are likely to end up at the same beach for C&C reasons.

[Tempest5]

Considering the Japan '45 campaign I wrote the AAR for stopped shortly after it was started, it's hard to tell how things would have ended up in detail but some issues were already visible.

Japan '45 and Japan '46 share many unit stats, but the differences between the campaigns also make the issues different.

There are system/mechanic related issues, scenario issues in terms of the values/schedules used and balance issues caused by the actual plans (which the designer can't really do anything about).

In the case of Olympic, none of the corps can support the corps at other beaches and one of the landings is extremely exposed to Japanese counterattacks. Weather conditions also make promises of constant air support unrealistic.

In the case of Coronet, the follow-up corps only arrive after a month aside from XIII Armored Corps, possibly due to logistics. Japanese reinforcements arrive within days.

I might as well discuss other balance issues here, aside from unit stats which I'll post later.



There are two values in the parameter data dialogue that stand out: the first one is the Japanese recovery rate of 2%, which combined with an overall higher unit quality (effective rate is 3% for B quality units) and plenty of units to hold a line make it more difficult to inflict long term losses through attrition.

The second are the breakdown rates. The campaign features mediocre to poor weather conditions in March and high movement cost terrain for tracked units. Pershings also have Low Reliability. The Allied breakdown rate of 8 means I'm losing a vehicle when moving 1 or 2 hexes in difficult terrain quite often.

That would be less of an issue if US Army tank battalions were not composed of 3 different tank types, the Chaffee, the Sherman and the Pershing, which make loss recovery less efficient as bigger units equals quicker more replacements as the maximum unit size is used as a base when calculating replacements. You also can't combine and breakdown all units in the battalion in case one unit regains strength more quickly or is full strength whilst others are not.

Breakdown losses combined with excellent Japanese AT values can quickly knock a tank battalion down a size if left at the frontline. Not entirely unrealistic, but the rate feels excessive. That's also why I prefer to keep tanks other than the Pershings out of reach of Japanese infantry aside from the cavalry units that don't have a range 1 hard attack.

Tank tactics for the Marines are slightly different as they don't have 76mm equipped Shermans and thus don't have a range 2 hard attack. That means I need to watch out for Japanese medium tanks and SPAT units as well.

Breakdown rates are also fairly harsh for the Japanese, but they have A and B quality tank units which reduce breakdown rates. Thus far, they've also been closer to roads.

As for the release schedule: the designer, in both the "narrative" he wrote for the campaign and the scenarios with later start dates assumes a very limited number of Japanese reinforcements will move to the beaches. In reality, most units can start to move towards the invasion beaches within days.

On the 12th of March, every single Japanese unit is released, including all the irregular/militia units in Tokyo. By that point, most of the other divisions are already at the front. You're facing a serious numerical disadvantage as the Americans, which is particularly difficult to overcome in the Eighth Army sector.

As Elxaime, my opponent, also posted in another thread, the Japanese command structure isn't very flexible due to the way the reattachment mechanic works: units assigned to a corps HQ can be reassigned, but not units above that level and the majority of the Japanese units are assigned to an Army-level HQ. That means units belonging to a certain army are likely to end up at the same beach for C&C reasons.

Thanks for assembling this informative AAR.
One item I found intriquing - as a possible mod-is this observation you made Engineer units...

As in Japan '45, a good part of the initial landing depends on chance in terms of whether your units disrupt as neither the divisional engineer units or the corps engineer units have an on-map HQ and will thus recover more slowly when Disrupted. Adding floating HQ's that withdraw when the "real" HQ arrives would help.

So instead of a BB/CA/DD you would have an Amphibious Forces Flag Ship (i.e.USS Eldorado) with the requisite HQ's attributes.
Would this unbalance the scenario?
https://en.wikipedia.org/wiki/USS_Eldorado_(AGC-11)

[ComradeP]

I don't think it would unbalance the scenario. It would make the initial landing go a little smoother for the Americans, but that's not necessarily a bad thing.

Unless you get off the beaches in the opening turns and land units in phases instead of when they arrive, you're going to take a beating on the beaches.

Floating HQ's would help with Disruption and ammunition checks.

Though I made the comment about Engineers, it also applies to the tanks and LVT's that land, as those also won't have an on-map HQ for a while.

The situation is worse for Corps troops, as the Corps HQ arrives later than divisional HQ's. Divisional HQ's arrive on turn 4 and 5, Corps HQ's on turn 11.