Japan '45 Historical Plan/Placement Olympic

[ComradeP]

It's been a while since I wrote/completed an AAR, and the release of Japan '45 seemed like a good time for a new attempt at doing so.

I'm playing a slightly modified version of the Olympic HP scenario against Sgt Jasper (from now on: John). The modification consists of a supply source on Shima Jima. It has no effect on gameplay other than to stop the Japanese units on Shima Jima from appearing in the Isolated units part of the command report each turn. For all other intents and purposes, it's the regular Historical Plan/Placement version of Olympic.

The main difference between Olympic and HP Olympic, aside from Japanese positions being slightly different, is that I Corps and XI Corps drop 2 divisions on the beaches each in the HP variant, but the full corps in the regular variant.

As I wanted to try the historical plan and John was fine with that, we picked the HP variant.

There will be all sorts of random musings about mechanics and the like in the AAR, so I apologize in advance if the narrative trails off from time to time.

It's difficult to estimate how tight victory points are going to be, as most points tend to come from losses in campaign games. It's worth noting that, though a campaign game, unit count is not very high as the US only have about 12 divisions and the Japanese 20 or so divisions/divisional equivalents.

The Japanese also need to move a lot of tiny heavy/support weapons units around so have more units to move, but it's still quite manageable compared to the bigger PzC campaign games out there like Moscow '42 and France '40.

First, we'll take a look at the island we're fighting on/for: Kyushu. The US goal is to occupy most of the southern half of the island. The Japanese player wants to prevent that.

The screenshot below comes from the one of the planning maps, with information that I've added to show where US forces come ashore.



As you can see, US forces arrive at three corners of southern Kyushu.

The good: it forces the Japanese to split up their forces.
The bad: each corps is too weak to accomplish much by itself, artillery/air/naval support isn't concentrated, each advance can be contained if there is no simultaneous progress elsewhere.
The ugly: The Japanese can Tennōheika Banzai! I Corps off the beach.

What makes little sense to me is why US planners wanted to stage a landing on an island roughly the size of Indiana as if it was just another island in the Pacific. The lack of any real concentration of force and firepower is a big problem and I Corps is in serious risk of being destroyed. Two landings with 2 corps each, either at two opposite locations or in Shibushi Bay and the Miyazaki area seem more logical, but this might be one of those plans that could've worked in real life but don't work well in a game.

Reinforcements, consisting of 3 additional divisions, arrive after a few days through a strategy choice. 2 divisions can land in any sector.

The 98th can land behind the USMC or at Shibushi Bay. It can also stage its own landing on the south-western tip of the island. As it's my only C quality division, that would be like throwing an egg at a wall and hoping the wall breaks instead of the egg.

[ComradeP]

Both sides have good units, with the Japanese having a variety of divisional organizations and various flavours of infantry units.

The US have mostly standardized divisions with tank and engineer battalions attached.

Japanese soft attack values are not great, but their battalions are big, some of their divisions have 4 regiments and many divisions are A or B quality, giving them a nice quality fire modifier of 25% (the modifier bonus of 10% is multiplied by 2.5) for B quality units and 50% for A quality units.

The Japanese also have a large number of tanks, but Japanese medium tanks are light by Western standards. Japanese tank destroyers are pretty good, however.






It's the size and quantity of Japanese battalions in particular that worries me, as US regular infantry battalions only have 579 men and Japanese battalions usually have 740 or 860 men. USMC battalions have 726 men.

Japanese divisional artillery consists of 75mm infantry guns and 75mm guns mostly. Infantry AT assets are very limited, AA units are scarce.






Nearly all US formations are (mostly) B quality. The 1st Cavalry Division is A quality, and the 98th Infantry Division is C quality.

Marine Divisions have 60 LVT(a)4's on paper.

[ComradeP]

The beaches are usually not strongly held and only have a density 1 minefield.

Beach hexes have a 200% terrain fire modifier, so you want to get off the beach ASAP as with alt direct fire and optional direct fire results, losses are scaled by unit size/density so hanging around on the beach with big units means taking serious losses.

40% of the US units will lose strength upon landing due to the Invasion Loss percentage, losing up to 45% of their strength.

I'll post the starting situations of the start of turn 2, 3, 4 and 5 for each sector (after my move and the Japanese response for turns 1,2,3 and 4). Strategy talk will follow, as a lot will depend on how the Japanese respond to my moves.

USMC landing zone:

The 2nd Marine Division (landing on Stutz Beach) and 3rd Marine Division (landing on Winston Beach) initially faces the C quality old-style 303rd Division which means they have an easy landing compared to the other two corps.

9 LVT® units support the landing. They've already been withdrawn in the first screenshot.

Though the landing is easy, they land in an area surrounded by hills. They need to break out of their beachhead as soon as possible, as there are two Japanese divisions further south and one potential reinforcement division that can reinforce the 303rd in the opening days.



The LVT®'s reduced Shimahira and Minatamachi to rubble. Shimahira was secured.

If you deselect Clear Mines or Rubble, you can assault with engineer units on turn 1. Remember to toggle it back on if it fails to remove the Japanese defender.

[ComradeP]

The Shibushi Bay landings have been successful in the sense that the first row of beach defenses have been cleared, but it will take a while before the divisions can shake hands. They'll have to attempt to do so, as the Americal Division is scheduled to land on the Dusenberg and Essex beaches between them.

The A quality 1st Cavalry Division lands at Ford Beach and the B quality 43rd Infantry Division lands at De Soto beach.

The A quality 86th Division defends the beaches.

Shibushi was reduced to rubble by battleships and bombers, always a good move to prevent reinforcements from moving in.

The orange counter in the east is a Ranger battalion.

In case you're wondering why there are units still on the beach: the supply sources for the two divisions are in a rather inconvenient location, so I'll have to hold those hexes in order to prevent being Isolated.

[ComradeP]

And now for the problem child.

Whoever planned this really dropped the ball with the I Corps landings.

Two divisions land on opposite sides of a major river in the only area held by two Japanese divisions, and four regiment divisions at that, with two more divisions and a brigade that can move in before reinforcements from IX Corps can arrive.

The B quality 33rd Infantry Divisions lands at Chrysler Beach facing the B quality 154th Division.

The B quality 25th Infantry Division lands at Cord beach facing the B quality 156th Division.

The second wave B quality 41st Infantry Division can land at either of the two beaches, player's choice.

As you can see, losses can mount quickly, but most come from arriving units taking an Invasion Loss hit.

The stacks on the beaches in the later screenshot are out of Japanese line of sight, with the lone tank companies blocking line of sight from the north.

[Landser34]

I found during playtesting that the army will have a hard time getting off the beaches I agree with the you 1st Corps has the hardest time and if not careful can be wiped out by the Japanese.I agree with your assessment whoever thought this plan was a good idea to land 3 corps where they had no chance of supporting each other. I would have had everybody land at the Marine beaches they get off the beaches easier than the Army does. The key to limiting heavy losses to units is you have to do what ever it takes to get off the beach hexes.I'm looking forward to your .AAR

[ComradeP]

Operation Downfall, the planned invasion of the Japanese home islands consisted of two stages.

Stage 1: Olympic (invasion of southern Kyushu).
Stage 2: Coronet (invasion of central Honshu).

The Operation Olympic as seen in the game is similar to the original plan, but with different landing locations and 4th Marine Division being swapped with the 2nd Marine Division.



May 1945 Olympic Plan pdf download: http://cgsc.cdmhost.com/utils/getdownloa...singleitem

The original plan envisioned landings in Kagoshima Bay and Ariake Bay, but somewhere along the line the plan was changed to the plan as seen in the game.

The short-term follow-up divisions and AFPAC reserve divisions are not in the OOB, though the 77th arrives a bit earlier than on the employment plan above. The 40th Infantry Division is off-map securing various smaller islands.

There's a "Take Kyushu" campaign scenario, but there might've been some version mix-up between designer and the person compiling the release files as that scenario still only includes the standard US OOB without follow-up units (the US OOB is identical to the one in this campaign scenario).

US military and civilian leaders were very worried about the Japanese build-up in Kyushu. The original plan was made on the assumption that there would be 3 division in southern Kyushu on X-day and that those would be reinforced by about 7 more within a short amount of time. In reality, that number was already reached by late July/early August.

https://www.cia.gov/library/center-for-t...-decision/

From the publication linked to above:

Allied planners feared a 1:1 manpower ratio fight. In the game, it's closer to 1:1.5 or 1:2 in Japan's favour.

What makes the game difficult for the Allied player is that the Allied OOB contains the divisions that were originally scheduled for the landing, whilst the Japanese OOB consists of the August OOB with units that were on the island or redeploying to Kyushu when Japan surrendered.

[ComradeP]

Wartime estimates by the Japanese mention US divisions have many times the firepower of a Japanese division. That's not really the case in the game, as Japanese divisions are bigger, Elite and 1st Line infantry (and my Marine battalions) have Defense values of 18 instead of the usual 16 and artillery is underpowered compared to its historical equivalent. At best, you can achieve a 2:1 firepower ratio.

Japanese MG and AT units are also on-map, whereas US MG units are abstracted. Both sides receive AT and battalion/regimental infantry gun and cannon units.

It's difficult to take out Japanese units, as the Fanatical Nations rule makes them immune to taking additional losses when unable to retreat (normally 50% remaining strength lost per enemy assault) and the optional rules in use make it difficult to kill small units through (in)direct fire. I still have to figure out if I should be isolating and attacking Japanese units or should try to bump them out of the way.

The naval support looks impressive, but ships use 1/2 global supply value to check for availability which means that with a global supply value of 60 halved to 30, they'll only be able to fire every 3-4 turns. US beach supply sources have a supply value of 60.

With local supply values being around 40 aside from near Shibushi Bay, Japanese artillery can fire every 2-3 turns mostly.

Interdiction is strong on paper but usually weak in practice as the game randomly selects an enemy air unit to roll for interdiction. As many US air units are small carrier fighter/bomber or light bomber units with low Soft Attack values, interdiction units are not particularly stiff unless the game picks a "Napalm" unit with high Soft Attack values.

Air visibility limitations are generous, as 50% of my air units can fly at a visibility of 2 hexes, which helps, though there are only 2 days (with Programmed Weather on) where visibility can drop below 3.

There are no dawn or dusk turns, and there are 3 night turns, which is a new experience for me as all the other PzC/FWWC I've played thus far had dawn/dusk turns and 2 night turns .

[ComradeP]

Start of turn 6, the last daylight turn of X-day.

The USMC makes good progress and will clear the ridge overlooking the beaches from the east soon. The northern ridge probably won't be cleared until X-day +1.

I mistakenly placed some of the USMC artillery on the beach instead of waiting until nightfall. The two units lost 5 guns in total.

Everybody else is trying to make progress in tiny steps.

[ComradeP]

The start of turn 7, the first night turn.

The USMC moved forwards again, about half of the forces in the other sectors are resting.

I Corps is already under pressure, though most battleships were available for fire support and mauled two Japanese units in the open.

Helpfully, the third regiment of both the 25th and 33rd Infantry Divisions doesn't land until morning on X+1. I'm not sure if I'll land them, or if I'll postpone their landing until other forces reach Miyazaki after the likely destruction of I Corps.

I don't think I've mentioned it yet, but the naval units are from front row to the rear: destroyers, light/heavy cruisers, battleships.

The brown counters are two Royal Navy battleships: the HMS Howe in Shibushi Bay and the HMS King George V in the Miyazaki sector.

Thus far, the USS Taussig and the USS Indiana have been withdrawn from the USMC sector. The USS Barton has been withdrawn from the Miyazaki sector. Ships have a 2% chance to withdraw each turn starting on the 10:00 turn (turn 3). Japanese coastal artillery knocked out a few destroyer turrets, but no ships were sunk yet.