Operation Invasion: Reaching the Japanese Mainland

Guiding Question:

Given its challenges, was the Allies' Island Hopping Campaign the best strategy for fighting World War II in the Pacific Theater?


Students will discover the necessity of the island-hopping strategy used in the Pacific Theater through interactive activities and creative problem solving. They will analyze primary sources to gain a fuller understanding of the toll the strategy took on those fighting on the islands. At the end of the lesson, students will use interactive technology from the American Battle Monuments Commission and maps to determine if the path the Allies took through the Pacific was the best way to reach the Japanese homeland.


Historical Context

The battle for the dominance in the Pacific Theater was a hard-fought, bloody affair that pushed the American military to develop new strategies of waging war. The key to Allied victory was the island hopping campaign, which required the military to fight for control of small, unknown islands across the vast Pacific Ocean. Though this campaign was essential to winning the war against Japan, the importance of Pearl Harbor and the dropping of the atomic bombs overshadow these battles in many school curricula. This lesson brings attention to overall strategy of the Island Hopping Campaign with specific focus of the savage battles and the grave toll it took on the men who sacrificed themselves to carry out the mission.


At the conclusion of this lesson, students will be able to:

  • Describe the overall process and reasoning behind the island-hopping strategy in the Pacific;
  • Analyze primary and secondary documents;
  • Use critical thinking and creative problem-solving skills to plan and evaluate a path from the United States to Japan; and
  • Evaluate the path the Allies took and determine if there was a better invasion route.

Standards Connections

Connections to Common Core
CCSS.ELA-LITERACY.RH.9-10.1 Cite specific textual evidence to support analysis of primary and secondary sources, attending to such features as the date and origin of the information.
CCSS.ELA-LITERACY.RH.9-10.2 Determine the central ideas or information of a primary or secondary source; provide an accurate summary of how key events or ideas develop over the course of the text.
CCSS.ELA-LITERACY.RH.9-10.3 Analyze in detail a series of events described in a text; determine whether earlier events caused later ones or simply preceded them.

Connections to C3 Framework
D2.Geo.4.9-12. Analyze relationships and interactions within and between human and physical systems to explain reciprocal influences that occur among them.
D2.His.1.9-12. Evaluate how historical events and developments were shaped by unique circumstances of time and place as well as broader historical contexts.
D2.His.8.9-12. Analyze how current interpretations of the past are limited by the extent to which available historical sources represent perspectives of people at the time.


Activity One:

Activity Two:

Activity Three:

Lesson Preparation

  • Set up classroom technology and test all online resources before class.

Activity One:

  • Set up the class or hallway for the Bell Ringer activity.
    • Use tape or other object to indicate the starting (United States) and ending (Japan) points. Be sure they are fairly far apart to ensure a student cannot move from the start to the end in just one jump. Use the Island Hopping Activity Sample Layout as a model.
    • Using masking tape or painter’s tape, set up a hallway or open area using the Island Hopping Activity Sample Layout.
    • The Xs will stand for places the student cannot jump.
    • The Is will indicate where the student can jump with one foot.
    • The IIs will indicate where the student can jump with two feet.
    • Be sure to spread out the Xs, Is, and IIs so that it is not easy to jump the whole way and students need to think about their path before they jump.
    • Depending on time and space available, feel free to make several paths.

Activity Two:

Activity Three:

  • Make one copy of the Calculation Sheet for each student.
  • Print one copy of the Event Cards (print double sided) for each group of three to four students. Cut up cards in advance.



Activity One:Bell Ringer (10 minutes)

  • Teacher Tip: Follow the Lesson Preparation instructions and the Island Hopping Activity Sample Layout to set up this activity.
  • Challenge students to cross the Pacific. Students will need to go from the starting point (the United States) to the end point (Japan). Rotate students to allow as many to participate as possible.
  • Explain to students:
    • The goal is to jump your way from the United States to Japan.
    • The Xs stand for places you cannot jump on OR jump over.
    • The Is indicate where the you can jump and land with one foot.
    • The IIs indicate where the you can jump and land with two feet.
    • You must decide your path, and the goal is to get to Japan as quickly as possible.
  • Teacher Tip:Be sure to set up the activity so that it is too far for a student to jump from the start to the end. Students will need to jump between the I and II locations while avoiding the Xs. The different markers represent the different types of islands from which the Allies could select:
    • The Xs represent an island that was not tactically useful (i.e., too small to support forces, protected by enemies, composed of unsuitable terrain, etc.);
    • The Is represent an acceptable island but with limited resources or tactical use; and
    • The IIs represent an ideal location (i.e., an island with an airfield).
  • After students have completed the activity, discuss some of the issues they faced and what they had to take into consideration when deciding where to jump. Ask the students to identify what they believe is the shortest, safest route between the United States and Japan.
  • Ask the students: What would alter the route you chose? Are there factors that would make you want to go closer to, or further away from, the islands and landmasses nearby?
    • Challenge students to think about all of the different factors that went into the decision-making process when selecting where to jump next.
  • Teacher Tip:If time and space allow, consider making the activity more challenging by requiring students to move items with them to represent supplies (i.e., textbooks, beanbags, etc.) Students could be required to move eight items from the start to the finish. When jumping to I spaces, a student would only be able to jump with one item (requiring him or her turn around and shuttle supplies.) When jumping to II spaces, the student could carry two items, as long as the jump could still be made. This would simulate the importance of resources, the time needed to transport materials from place to place, and the bottlenecks created by many of these small islands.

Activity Two:Primary Document Case Study (30 minutes)

  • Give students the War in the Pacific Overview.
  • Ask a student to read each section to give a basic understanding of the island-hopping strategy in the Pacific. This reading will set up the interactive map activity for students to better understand the decision-making process of the Allies.
  • Divide the class into groups of three to four students and give each student a Guadalcanal Case Study Packet
  • Ask students to analyze the primary sources in the packet to better understand what life was like for the Marines and soldiers who invaded the islands throughout the war.
  • Direct students to complete the guiding questions that accompany each document.
  • Allow time for students to share reactions to the primary sources.
  • Tell students,Now that we have had a chance to understand the strategy and the effect it had on those fighting, it is your turn to plan the invasion. Your objective is to map out the most effective route from the United States to Japan. Keep in mind the realities of battle and attempt to take the path that will cost the fewest number of lives.

Activity Three:Understanding the Island-Hopping Campaign (60 minutes)

  • Arrange students into groups of three or four students. You may choose to carry over the same groups from Activity Two.
  • Give each group of three to four students access to a computer and the World War II: A Visual History interactive timeline from ABMC.
  • Project the Areas Under Allied Japanese Control Map in front of the classroom.
  • Distribute one Calculation Sheet to each student.
  • Distribute one set of Event Cards to each group, but tell them they can only select one card at a time.
    • Challenge students to think about all of the different factors that went into the decision-making process when selecting where to jump next.
  • Direct groups to place all of the cards so that only the name of the campaign and the number are visible to them.
  • Explain to students that they will need to decide which path to take to get to Event Card 14, the Japanese Surrender. They will only have a limited amount of time to do this.
  • Ask a student to read the objective on the Calculation Sheet. Check for understanding.
  • Tell students, Everyone is starting at Pearl Harbor with 100,000 units of supplies and 65,000 men. I will keep track of the time and let you know when it is time for your next move.
    • Tell students to use the World War II: A Visual History interactive timeline, read what happened at Pearl Harbor, and summarize what happened on the Calculation Sheet.
  • Set a timer for five minutes. At the end of that time, tell students to flip over Event Card 1 (Pearl Harbor) and read the card. This card will direct students to Guadalcanal.
    • Tell students to use the World War II: A Visual History interactive timeline, read what happened at Guadalcanal, and summarize what happened on the Calculation Sheet.
    • Teacher Tip: From this point forward, student teams will need to make a choice of where to go next. Each choice has consequence (positive and/or negative) for supplies and manpower. Students will follow the same process for each move the rest of the activity.

  • After five minutes, tell students they need to select the next location.
    • Find an event on World War II: A Visual History timeline and take notes.
    • Flip the matching event card and fill in the impact on manpower and supplies. Calculate the impact (positive or negative).
    • Repeat the process until they get to Card 14 (the Japanese surrender).
    • Continue to track the time (five minutes for each move) and monitor students by answering questions and keeping them on task.
  • Assign students to complete the Reflection Question at the end of the Calculation Sheet. This can be assigned for homework if needed.

Assessment Materials

  • Choose an assessment prompt to assign to students (or allow students to choose between the
    • Prompt 1: In your opinion, was the path the Allies took the most effective way to reach the
      Japanese mainland? If yes, use at least three pieces of evidence from the lesson to defend
      the path. If not, suggest a more efficient path and support your new route citing at least
      three pieces of evidence from the lesson.
    • Prompt 2: Write a letter home or a journal entry describing what life would have been like
      for a Marine taking part in the Island Hopping Campaign in the Pacific. Use specific details
      from the Guadalcanal case study to support your writing.
  • The Writing Assessment Rubric can be used to score the essay.

Methods for Extension

  • Students with more interest can research the conflicting interests of the U.S. Army, Navy, and U.S. Army Air Forces in the planning of the Island Hopping Campaign. In the free response activity, students could discuss the different factors that were taken into consideration and what each branch of the military wanted to do.
  • Students can research some of the campaign’s major battles and compare and contrast the battles.


  • Teachers can adapt this lesson by having the class, as a whole, work through Activity Three.
  • Teachers can split the class into different groups to represent the competing interests and have the class debate the best path.
  • Teachers can break the case study into different stations instead of a single activity and jigsaw student responses.
  • Teachers can direct students to recreate a beachhead landing if time and space is available.


Return to Activity

Primary Sources

Secondary Sources

Other Sources