Hearts of Iron 4 (HOI4) – How to Increase World Tension

Guides

What is World Tension?

Hearts of Iron 4 is a World War 2 grand strategy game that aims to realistically simulate the events of that time for players to experience and lead any country to victory or defeat.

The game introduces a mechanic called “World Tension” to reflect the general mindset of the era and the readiness to take military action against aggressors globally.

This mechanic tracks the uneasiness of the world and the willingness to engage in military actions, allowing players to take actions that were initially unavailable at the beginning of the game, resembling the cautious approach of the Allied powers while the Axis powers were rapidly expanding.

To increase World Tension in Hearts of Iron 4, players can justify war goals on countries, declare war, send volunteers, or join a faction. These actions and more contribute to escalating World Tension, especially through negative interactions with other countries.

How to Increase World Tension in HOI4

In Hearts of Iron 4, the most common way to increase World Tension is by declaring war on a country. However, certain thresholds need to be reached before most countries can take such actions.

Here are the ways World Tension can increase:

  • Declare war
  • Puppet, annex, or take land through peace deals or focus tree events
  • Send volunteers
  • Join a faction
  • Justify a wargoal
  • Revoke a guarantee

Fascist or communist countries have an easier time raising World Tension compared to democracies, as most actions by the former affect World Tension while the latter have limited options. Justifying war on faction leaders like the UK can significantly raise World Tension.

By carefully justifying war goals on countries, players can increase World Tension rapidly and strategically, allowing for potential conflicts to be managed more effectively.

Increasing World Tension as a fascist or communist country should be done cautiously to avoid empowering democratic countries to interfere in their affairs.

Who Needs to Increase World Tension?

Only two countries in Hearts of Iron 4 require specific World Tension thresholds to be met before completing unique national focuses:

In Canada, reaching 5% World Tension is necessary to complete the Shadow Factories focus, and 20% for Defence of Canada Regulations, crucial for unlocking essential focuses in Canada’s national tree. For ahistorical paths, 15% is needed for the Dominion of Canada Rifle Association.

The United Kingdom has several focuses that require high World Tension percentages. For example, a 50% World Tension threshold is needed to remove The War to End All Wars debuff, delaying access to key focuses until certain historical events occur.

How World Tension Affects Game Mechanics

World Tension in Hearts of Iron 4 dictates the diplomatic options available for different ideologies:

Justify War goal

  • Democracies: 100% World Tension
  • Non-Aligned: 50% World Tension
  • Fascists and Communists: any World Tension level

Guarantee independence

  • Democracies: 25% World Tension
  • Non-Aligned: 40% World Tension
  • Fascists and Communists: same ideology countries only

Create faction

  • Democracies: 80% World Tension
  • Non-Aligned: 40% World Tension
  • Fascists and Communists: any World Tension level

Start Lend lease

  • Democracies: 50% World Tension
  • Non-Aligned: 60% World Tension
  • Fascists and Communists: 50% World Tension

Send Volunteers

  • Democracies: 50% World Tension
  • Non-Aligned: 40% World Tension
  • Fascists and Communists: any World Tension level

All Events in HOI4 That Increase World Tension

The following events in Hearts of Iron 4 lead to an increase in World Tension until it reaches 100%:

  1. 11 March, 1936 – Rhineland, +5% World Tension
  2. 17 July, 1936 – Spanish Civil War, +0.5% World Tension, Volunteers +2% World Tension
  3. 16 December, 1936 – Anti-Comintern Pact, +2% World Tension
  4. 1936 – Ethiopia Capitulates, +1.2% World Tension. Total World Tension at the end of 1936 = 8%
  5. 21 March, 1937 – Anarchist Spain, +0.5% World Tension
  6. 14 July, 1937 – Marco-Polo Bridge Incident and Sino-Japanese War, +8.8% World Tension. Total World Tension at the end of 1937 = 13%
  7. 10 February, 1938 – Anschluss, +12% World Tension
  8. 3 August, 1938 – Bulgaria Focus, +1% World Tension
  9. 7 September, 1938 – Sudetenland and Hungary Focus, +5% World Tension. Total World Tension at the end of 1938 = 25%
  10. 25 January, 1939 – Eastern Claims, +3% World Tension
  11. 5 April, 1939 – Fate of Czechoslovakia, +5% World Tension
  12. 11 May, 1939 – Albanian Occupation, +2% World Tension
  13. 14 June, 1939 – Italy Joins Axis, +1.4% World Tension
  14. 19 July, 1939 – Baltic Claims, +1% World Tension
  15. 23 August, 1939 – Danzig or War, +13% World Tension, Capitulation +3.1% World Tension
  16. 3 October, 1939 – Germany attacks the Netherlands, Belgium, Denmark, and Norway. USSR attacks Finland, +39.1% World Tension. This leads to WW2 and 100% World Tension

That’s all you need to know about raising World Tension in Hearts of Iron 4!

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