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Schematic plan · World War II (Okinawa)

Iwo Jima - Into the Main Defenses

All battlesBattle of Iwo Jima: engagement 1 of 3The event in the chronicleWikipedia
A schematic plan, generated from the statistics of the CAA Database of Battles: the armies' size and width, the hours of fighting, the plan of attack and the outcome are as recorded; the ground and the positions are not.
Rolling, Bare groundCentreLeft wingRight wingReserveCentreGunsLeft wingRight wingReserveGunsArmourArmourSchmidt01 km2 kmN

One of the 3 engagements of the Battle of Iwo Jima recorded in the CAA Database of Battles (number 1 in date order). USA (US 5th Amph Corps, 33,915 men under Mg Schmidt) attacked Japan (Jap 2nd Ind Mixed Bde(+), 18,300 men under Gen Kuribayashi) in Japan. The CAA Database of Battles records 96 hours of fighting on a front of 4.7 km, a frontal attack against fortified defense, and that USA won. Losses: USA 6,845 (20%), Japan 15,615 (85%).

This plan is generated from those figures. It shows the shape of the battle the database describes: the size and width of the armies, the plan of attack and the outcome. It does not show where the units actually stood.

The armies

USA

Mg Schmidt

UnitArmMen
USA left wingInfantry6,746
USA centreInfantry8,994
USA right wingInfantry6,746
USA reserveInfantry5,622
USA artillery (474 guns)Artillery5,087
USA armour (144 tanks)Armour720
Mg SchmidtCommander—
In this plan33,915

Japan

Gen Kuribayashi

UnitArmMen
Japan left wingInfantry4,132
Japan centreInfantry5,509
Japan right wingInfantry4,132
Japan reserveInfantry3,443
Japan artillery (59 guns)Artillery885
Japan armour (40 tanks)Armour200
Gen KuribayashiCommander—
In this plan18,301

What the sources report

USAJapan
Strength, this plan33,91518,300
Losses, this plan6,84515,615

In the CAA Database of Battles

CDB90 no. 518, “Iwo Jima - Into The Main Defenses”, compiled for the US Army to study what decides battles. These are the figures a what-if engine can be calibrated against.

Fighting
96 hours
Winner
the attacker
Terrain
Rolling, Bare
Weather
Dry, Sunny, Temperate, Winter, Temperate
Defender’s posture
Fortified defense
Front width
4.7 km (attacker), 4.7 km (defender)
ForceStrengthLossesHorseGunsPlan and outcome
USAattacker33,9156,8450474Frontal attack; Penetration
Japandefender18,30015,615059Defensive/offensive plan; Frontal attack; Repulse; Annihilated

Attacker’s advantages logistics +1 · momentum +1 · initiative +1 · air superiority +1

CDB90 (US Army Concepts Analysis Agency, 1990), tidy edition by Jeffrey B. Arnold; data under ODC-BY 1.0.

Notes

On this reconstruction

Generated automatically from the statistics in CDB90. Frontages, depths, distances, the order of events and the terrain are schematic: they follow the recorded strengths, front widths, hours of fighting, tactical plan and outcome, not maps or accounts of the battle. The sources give no hours; the timing is conjectural.

Sources

Facts gathered from Wikidata (CC0), Wikipedia (CC BY-SA 4.0) and Wikimedia Commons (licence per file); the plan and its text are timeastra’s own.