Understanding the Two is One, One is None Concept

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We preppers love acronyms and catchphrases, don’t we? Store what you eat, eat what you store is a popular one. TEOTWAWKI stands for The End Of The World As We Know It, of course. I’m not sure why this stuff is so popular other than it might make you feel like you’re part of the club when you learn the meaning behind those letters and sayings.

One very popular catchphrase is, “Two is one, one is none.” You’ll hear this over and over in survival literature and in related forums and such online. I’m fairly certain this particular saying originated in the military, though which branch remains a mystery to me. I’ve had Marines, Navy SEALS, and Army Rangers all tell me it came from their group, so who knows for sure at this point?

That said, we’re not here to discern the etymology of the phrase today but to better understand the meaning and concept behind it.

image: variety of light sources with batteries on table illustrating two is one, one is none concept

The Basic Idea of Two is One, and One is None

The basic idea behind two is one, one is none, is to have multiple methods to accomplish certain goals and tasks. This redundancy means that when a piece of gear is broken or lost or loaned and not returned, you still have something that can perform the function. Essentially, part of emergency preparedness is expecting something to go wrong and preparing for it. Backups offer a little bit of insurance.

Example 1

For example, in your bug-out bag, you should have a few different ways to get a fire going. If all you have is a single butane lighter, what will you do if it runs out of fuel? Or gets lost? Or breaks?

When possible, I strive for three methods or pieces of gear to accomplish basic tasks. For example, in my fire kit, I have the following:

Example 2

I also have several different types of ready-to-light tinder:

Example 3

A sharp blade is one of the most important survival tools. That being the case, I typically have three of them with me at all times.

  • A sheath knife. My preference is for a GNS model from LT Wright Knives.
  • A folding knife. My current favorite is a Kershaw Thermite, though I have carried several others over the years, such as a Buck 110 and a Swiss Army Tinker.
  • A small multi-tool, such as the Gerber Dime, which I truly love.

The Multi-purpose Nature of Two is One, One is None

This whole idea behind having a backup or two for essential gear is one reason why multi-purpose items are a great idea. Rather than bog down your pack with a ton of stuff, you can cut down on weight while still achieving your goal of having multiple backups.

To accomplish this, take a good, hard look at your survival kit or bug-out bag. Do you have multiple ways to:

  1. Start a fire?
  2. Light up the night?
  3. Cut cordage, firewood, and other things?
  4. Signal for help?
  5. Navigate your way to safety?

For anything you don’t have at least three methods of accomplishing, take the time to figure out and add another one or two. Some may be multipurpose, such as a flashlight. That can help to light up the night and signal for help.

The Pro and Con of Multi-purpose Items

The upside of multi-purpose items is that you need to pack less overall in your bag, which means it weighs less. (Or you can pack something else in it, too, I suppose.)

The downside is that if it is broken or lost, you are now down by one item in at least two categories.

It’s your responsibility to weigh the cost/benefit of using a multi-purpose item. Just be sure to consider it rather than be caught off-guard in an emergency situation with two or more capabilities unavailable, not just one.

Applying Redundancy Beyond Bug-out Bags

This idea of redundancy and backups must also extend to your other preparedness areas.

What About Modern Conveniences?

Are many of the conveniences you rely on are powered by electricity? How will you accomplish these tasks if there isn’t electricity? Here are a few scenarios:

  • You store wheat berries and grind them into flour using an electric grain mill. Do you have a manual method that doesn’t involve mill stones?
  • All of your emergency lighting relies on batteries. What if life gets busy and those batteries you meant to buy at the store…are still at the store when the power goes out?
  • Your camping stove is your off-grid cooking method…and then you discover the valve is damaged and won’t couple with the propane tank. How will you cook or even heat water?

It’s important to consider these types of possibilities for things that are critical to survival and plan for backups.

What About Skills?

We’ve spent most of this article applying the concept of two is one, one is none to gear and supplies. Yet, it is just as important to talk about redundant skills.

Using the example above of fire kit redundancies, one must also know who to use each of these methods. If I include a ferro rod and striker but don’t know how to use them, I may be in a world of hurt when I NEED a fire to survive. Have I built fires before? Can I build them in windy conditions? Wet? Have I built them from just what is available in my environment, not using pre-made tinder and accelerants? Because what if I didn’t have those?

You see what I’m getting at? Just as it’s important to have multiple pieces of fire-starting gear, it’s equally important to have practiced the skills to use each of them.

Why is the two is one, one is none concept so important?

You may still think two is enough; there is no reason for any more. That may be true, but what if it isn’t? Imagine the simple scenario of an autumn hike. One of your party falls and injures themselves. They need medical attention. Your party splits up with one or more heading back the trail until they find a cell signal to call for help.

The group did have two flashlights, but after the split, each group has one. This is great until you realize the batteries are dead in one, or it was damaged in the fall.

Now one group has none, and it’s likely to get dark before you reach the trailhead.

If you think that is unrealistic, consider the following everyday scenarios that can easily deplete your emergency supplies:

  • Your child goes camping with Scouts. At the drop-off point, they realize they forgot their pocket knife (first aid kit, fire starters, whatever). Being prepared, you pull one out of the car bag.
  • At the playground, a child skins their knee and needs bandages. You use some from your bag.
  • At sports, your child twists their wrist / ankle very slightly. The only thing that makes it “all better” is wrapping it with some of the self-sticking bandages from your emergency bag.
  • You have one unopened bottle of water left to share with your sick child. You use the water bottle / cup out of your emergency bag to avoid sharing germs, later taking the bottle / cup into the house to wash.

In all those instances, it’s easy to forget and never replace the missing items. That’s an easy thing to do when times are good, and your safety and survival aren’t dependent on a flashlight, bandages, or a pocket knife. As a prepper, though, we keep worst-case scenarios in mind — times that might now allow for easy replacement of vital tools and gear.

Buy the Best Quality Backups Your Budget Permits

When we start out, many of our preps are often low-quality simply because we don’t know what we really need or what to look for to get good quality. These low-quality items often end up in various emergency bags. There isn’t necessarily anything wrong with that – honestly, I’m fine with the low-quality hammer and wrench in my car bag because they are truly just-in-case items I never, ever expect to use. But for critical areas like water, staying warm, and signaling, ensuring you have at least one higher-quality item could be a matter of life and death.

Going back to the example of a butane lighter, the simple fact is that many of us have lighters we picked up in the checkout lane as impulse purchases. These are almost always low-quality, disposable items. In decades past, high-quality refillable lighters were more widely available because smokers used them, and there were a lot more smokers in the USA. These disposable lighters aren’t refillable, and they are relatively easy to damage.

We all have budgetary limitations. Tossing in two cheap Mylar emergency blankets as backups for a higher-quality wool blanket or disposable lighters as back-up for storm-proof matches is perfectly reasonable. Personally, I know I have used my “emergency” wool blanket more than once. (We could have had a car accident if I hadn’t curled up on the sofa and napped while my son was in class – really!) Having backups is just good sense.

A Final Word

Skill and gear redundancy is good advice and a sound survival principle. Identify the gear and other goods your survival depends upon and then begin adding back-ups. You won’t be sorry.

In what ways do you have redundancies for gear and skills?

Originally published February 4, 2016; updated by The Survival Mom editors with contributions from Jim Cobb.

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Bethanne is an eclectic writer who lives in the exurbs (that's what comes after the suburbs) with her husband, sons, and cats. She has been writing for The Survival Mom since 2010. You can learn more about her books, including the "Survival Skills for All Ages" series, at BethanneKim.com.

4 thoughts on “Understanding the Two is One, One is None Concept”

  1. Pingback: Prepper News Watch for February 4, 2016 | The Preparedness Podcast

  2. Should you ever really be in a fix for fire and your lighter is empty, remember it will still make sparks…maybe not as well as the sparker you did not yet purchase, but you can get a fire going with one–I have done it!

    1. Absolutely! That “empty” lighter is never truly empty. Gather tinder, crack open the plastic casing, and saturate your tinder with it. Strike sparks from a smaller distance, making sure you don’t have lighter fluid on your hands.

      I still prefer to have a titanium rod and striker, a lot of waterproof matches, and an extra lighter–because fire is one of the most important survival tools we have. Mastering fire comes before mastering shelter because fire provides shelter and boiled water, in a pinch.

  3. Pingback: 9 Tips For Packing Your Bug Out Bag | Urban Survival Site

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