Just as advancements in technology shaped World War 2, researching new technologies plays a pivotal role in Hearts of Iron 4 campaigns. The research system will allow you to improve the equipment you use and unlock new elements to be used in designers.
Although factors like research speed and number of research slots will change depending on your country and starting scenario, the basic mechanics behind research will remain the same.
How to Research
All things related to research will be on the third button from the left with the other action buttons. Alternatively, you can press W to quickly open and close the tab.
From the research tab, you’ll see one row for each research slot you have open, as well as your cumulative research speed bonus and any limited time bonuses available. These will impact the amount of days it takes to unlock a new technology. Clicking one of these rows will open the technology tree.
Within the tech tree, you’ll see 9 categories at the top to view different types of research. The first seven options allow you to improve your military directly, either through flat bonuses or new equipment. The final two, engineering and industry, will provide general upgrades for your country, such as improved construction speed, better radar upgrades, and synthetic oil.
To research, select any technology with a yellow background to reveal details about it, including some historical context, what it unlocks, and how long it will take to research. If the technology is under a future year, there will be a penalty for researching it ahead of time. You can start the research by clicking the green Research button in the top right.
How to Research Doctrines
Although in the past you were able to unlock new land, naval, and air doctrines from research, you now have to discover new ones through the Officer Corps using the appropriate XP.
How to Research Transport Planes
At the start of your campaign, transport planes are already researched. You can start creating them by navigating to the production tab, clicking the “Build Aircraft” button, and scrolling until you find Transport Plane 1.
How to Research Carrier Planes
Returning players to Hearts of Iron might be confused by the absence of carrier planes in the air technology tree. This is because they are now automatically unlocked when you research the appropriate airframe—no need to waste a research slot!
Researching Faster in Hearts of Iron IV
Fortunately, there’s ample ways to improve your base research speed in Hearts of Iron to give you an advantage. A common and powerful way is through your country’s national focus tree. These research bonuses vary depending on the focus, but they often provide a boost of 100% to 300% faster research for specific technologies or an entire group of technologies.
This can be invaluable for rushing technologies while you ramp up for war. Keep in mind that timing is important for these bonuses, as they will automatically apply to the next eligible research you start.
Another way to improve research speed is through military industrial organizations. In the technology tree, you may notice some purple beakers next to certain techs. If you select a technology to view its details, you’ll be able to click the beaker to assign an MIO to the research. This provides a significant speed boost, usually a minimum of 10% faster at the start of the game.
A third, consistent way to improve research speeds is by researching certain technologies. Under the engineering tab, discovering the technologies in the mechanical engineering and computing track will provide a flat research speed buff.
When to Research Ahead of Time
Usually, you will want to wait until the ahead-of-time penalty is gone before researching, but there are times when it is worth researching something, even if it is a year or more in advance. This is typically most useful for a major equipment upgrade, such as discovering a new generation of artillery or tanks.
The ahead-of-time penalty is steep, with research time increasing by 200% for each year the technology is ahead of its intended time. Typically, without a bonus, you will want to wait until December of the last year of the penalty before starting research. However, with a research bonus—such as a 100% speed increase from a national focus—it can be feasible to begin research a year or two early, allowing you to unlock major upgrades ahead of the competition.
Acquiring new, more advanced technologies in Hearts of Iron 4 will be necessary to keep an edge over your opponents. Have any other tips or tricks for researching in Hearts of Iron? Let us know in the comments below!
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Lucky Boop
Strategy game enthusiast, especially Paradox titles and the Civilization series. Whenever he's not writing he spends his time watching sports, enjoying coffee, or studying history.
