General information on research Hearts of Iron IV Guide
Last update: 06 July 2016
The opportunity to research into your own technologies is one of the key factors on your path towards world domination. Depending on the nation that you play as, you can start as many as 100 research actions grouped in 11 fields. If you start the game with the scenario set in 1936, you will have only basic units. If you decide to start the game before World War II breaks out, your technology will be much more advanced.
In the course of standard game, you can have as many as 5 research teams that will be working at the development of new technologies simultaneously. The most important thing to know is that each research team can save research results for up to 30 days. If, after you have realized one project, you do not start another one, the fallow team will save results. This means that for up to 30 days, you can decide not to undertake any projects. However, if you exceed that time limit and you do not take interest in any of the projects, each day above the 30-day limit will be a lost one.
Each technology is bound with temporal threshold, as historically realistic as possible . Of course, in the course of the game, you will find many technologies that have been made universal to even the chances of each nation. Otherwise, you will not be able to build nuclear bomb in Tibet. If you play in accordance with historical facts, you have to devote to research amount of time resulting from the basic modifier, diminished by the bonus to research. If you decide to research into rare technology and you want to start your research before it actually (historically) started, you will be punished with ahead of time penalty calculated for each day before the actual date. You can reduce the penalty, and duration of the research, by realizing your selected national goals. This is the only way to avoid penalties of this type.
Of course, technologies are interconnected, where more advanced variants require discovery of the less advanced ones. As a result, Individual projects are blocked, if you work within the path. Of course, for one field, there are several paths , which is why you are not too restricted. Still, you have to remember that there are technologies that exclude each other. In the case of the national goal, researching into the variant that collided with the other ones blocked the possibility to change the chosen path. In the case of technologies, you can do whatever you please, but if you have already developed an entire line of products, where the first one collided with another path, the whole line will reset if you change the path.
The below table presents basic information on each of the available technology tabs.
Icon | Name | Commentary |
| Infantry | This tab provides you with access to basic gear for infantry and technologies that will passively boost statistics of each division Additionally, you can start your work on mechanized battalions. Also, you can define templates for paratroopers. You will be using this tab throughout the entire campaign. First of all, try to develop passive statistics of units and research into better versions of rifles. |
| Support battalions | Apart from basic gear for battalions, you gain access here to all types of support units. Remember that each division template allows you to add five units to standard offensive battalions. Appropriate choices can considerably increase combat value of your army. Try to gain access to basic battalion types at the very beginning of the game and modernize them in the course of the game. |
| Armor | This tab can be very extensive, which depends on the nation that you play as. For medium-sized countries, you can develop light, medium and heavy tanks. It should be noted that for each type of unit, you can develop three variants that allow you to build self-propelled artillery, tank destroyers or AA cannons. If you decide on building armored battalions, you should start research into this branch as soon as possible. |
| Artillery | In this part of the research panel you develop all types of support units. Thanks to it, you can develop three types of units - anti-aircraft, general rocket artillery and anti-tank rocket artillery. Each type of support will be especially valuable in specific cases, which is why you should not ignore this branch. Of course, apart from elements of gear, there also technologies that will passively affect its effectiveness. |
| Land doctrine | You can develop a number of useful factors, depending on the development path that you pick, which will prove especially effective in the case of land units. For detailed information, see the chapter that has been devoted to this branch. |
| Naval technology | The basic advantage from developing this technology is the possibility to build ships. Note that thanks to this branch, you can research into more effective landing of troops, which may prove useful against island nations and invasions territories on other continents. |
| Naval doctrine | Just like in the case of land armies, you can find detailed information in a separate chapter. |
| Air technology | In this case, all of the projects are focused on new models of units. Remember that availability of some of the projects depends on development of jet engines. Additionally, some of the units can be converted into machines that can start from and land on aircraft carriers. If you are a proponent of using aircraft, you should take interest in this tab early into the game. |
| Air doctrines | These are technologies that allow more effective planning and realization of specific actions. To learn more, see the chapter devoted to this topic. |
| Engineering technology | This type of research focuses on increasing the range of detection of possible threats. Additionally, you can develop here technologies connected with nuclear bombs and long-range missiles. You should conduct research here on a regular basis, especially when it comes to weapons of mass destruction. |
| Industry | This tab provides you with access to synthetic refineries and many modifiers profitable for your economy. You do not have to concentrate all your forces here, but right at the very beginning, it is a good idea to reduce time necessary to erect buildings, or to assemble all types of gear. If you have lots of natural resources, it is a good idea to increase profits that you receive from mining them. |
