Oda Nobunaga’s Tenka Fubu – Drawings are maps of battle!

Wisdom for manufacturing learned from warlords of the Sengoku period

Similarities between the Battle of Okehazama and the drawings

In 1560, Oda Nobunaga defeated the powerful Imagawa Yoshimoto, who commanded an army of 25,000 men, with only 2,000 soldiers of his own.
How was Nobunaga able to win the famous Battle of Okehazama against such overwhelming odds?

The answer lies in his ability to read maps accurately.

Before the battle even began, Nobunaga had already identified and controlled the key strategic points on the map.
To isolate the Imagawa forward bases of Narumi Castle and Odaka Castle, he strategically placed forts such as Zenshoji Fort and Nakajima Fort at precise locations.
These positions effectively cut off the enemy’s supply lines and communication routes, forming a tight encirclement.

Because of this fortress placement based on careful map reading, the Imagawa army—despite its size—was unable to move freely.
They were gradually forced into a narrow route toward the Okehazama area, exactly as Nobunaga had planned.

Nobunaga thoroughly understood the terrain, accurately predicted the enemy commander’s position using maps and intelligence, and launched a surprise attack along the optimal route.
Without the ability to read maps, this victory would have been impossible.

The same principle applies to modern manufacturing.

If you cannot read technical drawings, you cannot create precise products.
Technical drawings are the maps of manufacturing.

Nobunaga’s famous quotes and lessons

“Tenka Fubu” – Unify the world through military force

Nobunaga’s words are not just a declaration of war. They represent the spirit of “perfect preparation and precise execution.”
Applying this to manufacturing:

• Tenka = perfect product
• Bu = Technique and Skill
• Fu = To Spread and Bring into Reality

In other words, one way of thinking is to “create perfect products with precise technology and spread them around the world.”

Nobunaga’s lesson:

1. Preparation is 90% = Study the map and plan your strategy before you fight
2. Accurate information is vital = even a 1mm difference can lead to defeat
3. Don’t be afraid to innovate = Actively adopt new technology (guns)

What is a drawing? A super simple explanation

Drawing = Map of the Sengoku period

Just as warlords of the Sengoku period looked at maps before going to battle, people in the manufacturing industry look at blueprints.

What maps and drawings have in common:

Why do you need a drawing?

Imagine you work in a factory that processes parts.

If you don’t have a drawing:

• 　There is variation in quality
• 　Reproducibility is lost
• 　Material size is unknown

If you have a drawing:

• 　Stable quality
• 　Reproducible
• 　Can be made with the right material size

Drawings are “words.”

Anywhere in the world, even if you don’t speak the local language, you can make the same product as long as you can read the blueprints.

Third-Angle Projection Basics: Seeing an Object from Three Different Views

How castles were recorded during the Sengoku period

When Nobunaga built Azuchi Castle, how did the craftsmen share the same vision?

Answer: I drew a picture from three angles.

1. View from the front (front view)
2. View from the side (side view)
3. View from above (plan view)

This is the basis of third angle projection.

What is third angle projection?

Third angle projection = A method of viewing an object from three directions and drawing it on a flat surface

Three perspectives:

1. Front View – The front view of an object
2. Side View – A view of an object from the side
3. Top View – The top view of an object

Why do we need three directions?

Example: cube (dice shape)

Viewed from the front: ■ (square)
Viewed from the side: ■ (square)
Viewed from above: ■ (square)

→ They all look the same! It’s only when you see all three together that you realize they’re cubes.

Practice 1: Let’s read the box (cube)

Question: What shape is the following drawing?

Front view: 50mm x 50mm square
Side view: 50mm x 50mm square
Plan view: 50mm x 50mm square

Answer: A cube with sides of 50 mm (dice shape)

Key Takeaways:

• All three figures are the same → Cube
• All sides are 50mm → exact size
• With this information, we can make the same box anywhere in the world!

Practice 2: Let’s read the triangular prism

Question: What shape is the following drawing?

Front view: 40mm x 30mm rectangle
Side view: Triangle with base 40mm and height 30mm
Plan view: 40mm x 60mm rectangle

Answer: Triangular prism

Reading tips:

• Front view : Rectangular → “Has a flat side.”
• Side view : Triangle → “It has a sharp point.”
• Floor plan: Rectangle → “The whole is long.”

→ Combining three makes a “triangular prism”

important:
“It looks like a triangle when viewed from the side!” → This determines the object’s characteristics

Practice 3: Read your smartphone

Actual product: Smartphone (8mm thick)

Front view:

• 142mm long x 71mm wide
• Small circle at the top (camera)

Side view:

• Thickness 8mm
• Camera unit thickness: 4mm

Floor plan:

• 12mm long x 71mm wide
• Know the camera position

What this drawing shows:

1. Smartphone size (will it fit in your pocket?)
2. Camera position (important when purchasing a case)
3. Smartphone thickness
4. Button Location

Practice 4: Board with holes

Question: Read the drawing of the perforated board.

Front view:

• 100mm x 80mm rectangle
• 20mm diameter circle (hole) in the center
• The holes are depicted by dashed lines

Side view:

• 5mm thick wire
• The holes are “invisible” so they are dashed

Floor plan:

• 100mm x 80mm rectangle
• A 20mm diameter circle in the center

Important symbols:

• Solid line (━) = visible line
• Dashed lines (- – -) = invisible lines (hidden parts)

Reading:

1. Front view: Hole locations are visible (center)
2. Side view: You can see the thickness of the board (5mm)
3. Plan view: You can see that the hole goes through

• Hole position: Within ±0.5mm from the center
• Hole diameter: 20mm ± 0.1mm

各部面取りあり

Summary: 3 key takeaways from today

1.Drawings are “maps of manufacturing”

Just as warlords of the Sengoku period could not fight without maps, accurate products cannot be made without blueprints.

2.Third angle projection is “three eyes”

• Front view (view from the front)
• Side view (view from the side)
• Floor plan (view from above)

These three things will help you fully understand the shape of an object!

3.Being able to read blueprints can change the future

1. Communicating beyond language barriers → Drawings are a universal technical language. Even if you are not good at English, you can communicate accurately with overseas factories.
2. You will be able to see the overall picture of how things are made → You will understand why they are shaped the way they are and what the important parts are, making it more fun to make things.
3. Become a teacher on-site → Become a teacher who can teach things like why certain dimensions are used and why certain intersections are used here.
4. The cause can be identified → Even when a problem occurs, the actual item can be compared with the drawing to confirm whether it matches the drawing.
5. It will become a weapon you can use for the rest of your life → The ability to read blueprints remains the same even if you change machine tools or countries, so it will become a skill that will support you throughout your life.

Nobunaga’s words: “Tenka Fubu”
→ Make your career a success with the weapon of technology!

Next episode preview: Week 2 – Takeda Shingen

Title: Takeda Shingen’s Fuurinkazan – If you can read numbers you can win!

Contents:

• How to read numbers (dimensions) on drawings
• The world of mm (millimeters)
• Diameter (⌀) symbol
• What is tolerance?

Takeda Shingen’s famous quote:
“People are castles, people are stone walls, people are moats”
→ Accuracy of numbers makes the product strong

Stay tuned!

This week’s challenge mission

Mission 1: Look at the objects around you from three angles

Objects: erasers, smartphones, books, cups, etc.

assignment:

1. View from the front → Draw it on paper
2. View from the side → Draw it on paper
3. View from above → Draw it on paper

Goal: To experience “The shape of an object can be fully understood with three diagrams”

Mission 2: Find the blueprint symbols

Where to look?

• Furniture assembly instructions
• Electrical appliance manuals
• Search for “drawing example” on the internet

If you find it:

• Which is the front view?
• Which is the side view?
• Which is the floor plan?

Mission 3: Tell your friends

What we teach:
“The drawing is a picture seen from three directions.”

By teaching:

• Deepen your understanding
• Your friends can learn too
• We can grow together

Next steps

Week 2 : Learn how to read numbers (measurements)

Week 3: Learn drawing symbols

Week 4: Gain practical skills through comprehensive exercises

Your future starts with one step today

Oda Nobunaga took control of the country thanks to his ability to read maps.

Your ability to read blueprints can open up your future career.

First Step: If you’ve made it to the end of this article, you’ve already started.

Next Step: Take on this week’s challenge mission.

And: See you in Week 2!

Next episode: Week 2 – Takeda Shingen’s Fuurinkazan

団まごめ

戦国武将名言でものつくり

日本の戦国時代武将の名言をつかってものつくりの楽しさを皆さんに紹介していくブログです。どのような人物だったのかと名言を英語で紹介していきます。 好きなことを伝えたいために英語学習もはじめています。