A Guide to Research in Hearts of Iron 3

A Guide to Research in Hearts of Iron 3
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Research is a very important part of every game of Hearts of Iron 3. Without research your nation will fall behind the technology of the world and soon be faced against enemy units that are better equipped for war.

Like everything in Hearts of Iron 3, however, research is very complex. Opening up the initial research screen can be extremely daunting. This guide will help you make sense of research so that you know how to get an edge in technology and don’t have to always leave it up to the AI.


When you open up your research screen you will see a small section in the upper left called Distribution of Leadership. This represents the talent in your country. Having more leadership talent means that you have more educated people in your country who are capable of taking on vital roles. This includes not only the research of new technologies but also espionage, diplomacy and military leadership (in the form off officers).

The sliders dictate how your leadership is distributed. Usually you’re going to be fairly research-heavy here. The effects of your distribution can be seen at the top of the screen by hovering over the icons there. Hovering over the icon which looks like any envelope will tell you how much diplomacy you have, while hovering over the camera will tell you how quickly you are training new spies.

Research Que

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Below the leadership area you will see the current research area. This que lists all of the projects which you are currently involved in. The maximum number of projects you can research at once equals your research distribution in the leadership areas. You can que more projects than you have the ability to currently research, but the additional projects will be left on hold until other projects are completed.

It is beneficial to have your research que as full as it can possibly be, so don’t feel bad if you are researching fifteen technologies at a time. The status of technology being researched will slowly fill up to let you know the progress, and you will also see the estimated date on which research will complete.

The Main Technology Tree

Most of the research screen is taken up by the main technology tree. It actually operates more as a number of trees which are casually related. At the top of the screen you have the ability to select a different category of technology. Categories include infantry, armour, escorts, capital, bomber, fighter, industry, secret, theory, land, naval and air.

There are numerous symbols to pay attention to on this screen. The color indicates if the tech has been researched, can be researched, or is locked. Green techs can be researched, while gray techs are locked until you meet the requirements. The year indicator details when the technology was historically available - if you haven’t reached that year yet, the tech will be harder to research. The number with a circle around it indicates how tough the technology is to research. Tougher technologies take longer.

Finding out what a technology gives you is simply a matter of placing your mouse cursor over the technology and waiting for the tool-tip to appear. Some technologies will modify existing units, while other technologies will allow for entirely new units to become available.

Theoretical and Practical Knowledge

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At the bottom of the screen you will see a number of icons with numbers beside them. These icons represent your theoretical or practical knowledge of an area of research.

Theoretical knowledge is obtained through actual research. Practical knowledge is obtained by actually using technology in the field. For example, practical knowledge about armour is gained by actually using armoured units in combat.

This knowledge directly relates to your research speed. If you have a lot of knowledge about armoured units, for example, you will be able to research new advances in armoured units more easily than a nation which makes only moderate use of armored units. Practical knowledge is more valuable than theoretical knowledge, so make sure that you actually do use your units in the field.

To find out what type of knowledge a technology relies on, simply look at the icons which are listed on the technology and match them with the icons at the bottom of the screen. You will find that many technologies draw from more than one area of knowledge, but not all do.

Also, beware that knowledge can decay. If you do not make any use of an area of knowledge, you will find that your knowledge goes down over time. Once you become experienced in an area, be sure to maintain your knowledge!

Technology and Units in the Field

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Often a technology which you research will result in new equipment for existing units in the field. Units do not upgrade automatically, however, and they don’t upgrade based on anything which you can find in the research screen. Instead you’ll have to go to the production screen and adjust the upgrade area of that menu. This will automatically upgrade units to a new level of technology over time.

Once a unit is upgraded it will stay at the new level of technology without any further need for maintenance. Obviously, new units will start at the higher level of technology.

Ships operate a bit differently, however. As you research better ships you will gain access to better classes of ships. Older ships will be able to be upgraded to certain newer technologies, but this is not always the case.

You can also upgrade technologies which are not attached to units like radar stations and anti-aircraft installations.