science

War Plan Orange

War Plan Orange is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand War Plan Orange rather than just read about it. In short: War Plan Orange (commonly known as Plan Orange or just Orange) was a series of United States Joint Army and Navy Board war plans for dealing with a possible war with Imperial Japan in the years between the First and Second World Wars. It failed to foresee the significance of technological changes in naval warfare, including the submarine, air support and aircraft carriers, and although the Battle of Midway was impor…

Key takeaways

War Plan Orange belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect War Plan Orange to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of War Plan Orange from memory before moving on to harder problems.

Reference excerpt

War Plan Orange (commonly known as Plan Orange or just Orange) was a series of United States Joint Army and Navy Board war plans for dealing with a possible war with Imperial Japan in the years between the First and Second World Wars. It failed to foresee the significance of technological changes in naval warfare, including the submarine, air support and aircraft carriers, and although the Battle of Midway was important, and the US Navy did "island-hop" to regain lost territory, there was no culminating "showdown" battle as anticipated by Plan Orange.

Development

Informal studies as early as 1906 covered a number of possibilities, from basing at Gibraltar or Singapore, an idea revived by the British before World War II, to "a quick trans-Atlantic dash" to the Pacific. The plan eventually adopted was conceived by Rear Admiral Raymond P. Rodgers in 1911.

19 Dec 1919: Strategy of the Pacific (JB 325, Serial 28) 7 Jul 1923: Estimate of the Situation, Orange (JB 325, Serial 207) 15 Aug 1924: Joint Basic War Plan - Orange (JB 325, Serial 228) 10 Jan 1929: Revision of Joint Army and Navy Basic War Plan Orange (JB 325, Serial 280) 20 Jun 1934: Inadequacy of Present Military and Naval Forces Philippine Area to Carry Out Assigned Missions in Event of an ORANGE War (JB 325, Serial 533) 8 May 1935: Revision of Joint Army and Navy Basic War Plan - Orange (JB 325, Serial 546) 19 May 1935: Revision of Joint Army and Navy Basic War Plan - Orange (JB 325, Serial 570) 14 Oct 1936: Revision of Joint Orange Estimate of the Situation (JB 325, Serial 589) 9 Dec 1936: Changes in Joint Basic War Plan Orange (JB 325, Serial 594) 19 Feb 1938: Joint Army and Navy Basic War Plan Orange (1938) (JB 325, Serials 617 & 618) The plan was formally adopted by the Joint Army and Navy Board beginning in 1924. Predating the Rainbow plans, which presumed the assistance of allies, Orange assumed that the United States would fight Japan alone.

Strategy As originally conceived, it anticipated a blockade of the Philippines and other U.S. outposts in the western Pacific. They were expected to hold out on their own, while the Pacific Fleet marshaled its strength at bases in California and Hawaii and guarded against attacks on the Panama Canal. After mobilization (the ships maintained only half of their crews in peacetime), the fleet would sail to the western Pacific to relieve American forces in Guam and the Philippines. Afterwards, the fleet would sail north for a decisive battle against the Imperial Japanese Navy's Combined Fleet, and then blockade the Japanese home islands. The strategy was in keeping with the theory of Alfred Thayer Mahan, a doctrine to which every major navy subscribed before World War II, in which wars would be decided by engagements between opposing surface fleets, as they had been for over 300 years. Following the 1933 Operations IV Wargame, which resulted in defeat for a hypothetical blue fleet meant to symbolize a US Philippine relief force, War Plan Orange was revised to account for a more steady, methodical advance in order to take Japanese strongpoints in the Marshall Islands. This was done in accordance to observations that both stretched logistical capacity in the "through ticket to the Philippines" strategy, and inability to repair damaged vessels, allowed Japan to gain command of the sea via the neutralization of the US battle line force.

The game carried two implications, both of them fatal to the "thrusting" concept. First, it showed that underwater damage would likely trump whatever the fleet could do in the western Pacific at the outset of a war. Ships would almost inevitably be torpedoed, and they would have to go somewhere other than the Philippines for repairs. If enough of them had to be repaired at a rear base, the fleet would no longer be superior to Orange's. Given the agreements barring fortification of Far Eastern bases, only Pearl Harbor could repair U.S capital ships. Sending them back to Hawaii would forfeit the Far East to the Japanese. Despite this, the strategy followed by the U.S. in the Pacific War differed little from Rodgers' concept from 1911: a leapfrog campaign to conquer the Marshalls and Carolines (held by Japan before the war), liberation of the Philippines, and blockade. Absent was the "decisive battle" of Mahan, and of Japanese planning.

Japanese plans In accordance with the Kantai Kessen naval strategy, the Imperial Japanese Navy developed its own plan, that allowed the US Pacific Fleet to sail across the Pacific while the IJN would use submarines and carrier attacks to weaken it. The Japanese fleet would then attempt to force a fleet action against the weakened US fleet in a "decisive battle area", near Japan, also in line with Mahanian doctrine, which Japan had enthusiastically embraced. It was the basis for Japan's demand for a 70% ratio (10:10:7) at the Washington Naval Conference, which was considered necessary to provide Japan superiority in the "decisive battle area", taking into account that the US had naval commitments in other theaters, while Japan did not. It was also the basis of the United States' insistence on 60%, which amounted to parity.

… excerpt ends here. Continue reading the full article.

Worked examples

Example 1 — a first encounter with War Plan Orange

Start with the simplest possible case. Write down what War Plan Orange claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to War Plan Orange before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about War Plan Orange ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of War Plan Orange

In research: War Plan Orange appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses War Plan Orange in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: War Plan Orange is common in secondary-school and first-year university syllabi. It links to neighbouring topics Imperial Japanese Navy, Japan–United States military relations, Military doctrines, so understanding it makes those chapters shorter.
In everyday life: Look for War Plan Orange outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “War Plan Orange” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study War Plan Orange in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what War Plan Orange means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain War Plan Orange out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is War Plan Orange in simple terms?

Why does War Plan Orange matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study War Plan Orange?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on War Plan Orange.