Open Realm of Stars
A downloadable 4X space strategy game for Windows, macOS, and Linux
Open Realm of Stars is an open source 4X strategy game. Developed
using Java.
Explore the galaxy

Move your fleet in a randomly generated galaxy. Encounter other species, and find new planets to colonize. Explore mysterious space anomalies.
Manage your own planets

Manage your planets gain access to better buildings and ships. Population management is key to acquiring more culture, research, metal and production.
Have diplomacy with other space faring races

Make friends and enemies while traveling to outer realms. Form trade alliances, and defensive pacts to establish technology trade with other races. Make good diplomatic relations all other realms and win voting for ruler of the galaxy.
Deep space combat

Fight enemies with customizable ship designs. Ship components have their own hit points and energy requirements to use them. Components will be rendered useless if hitpoints are depleted or energy requirements are not met. This makes space battles dynamic. A lucky shot by allied ship to an enemies fusion reactor will make them immobile on the battlefield. Fleets with advanced technologies have significant advantages, however luck or number of ships can sway the battle in your favor.
Conquering the planets

Conquer enemy planets. Drop bombs to clear out enemy troops, then deploy your own ground troops to seize control. Regular space weapons can be used for causing suppression to defending troops.
Leaders

Each realm can have unique characters called leaders. These leaders can act as governors, fleet commanders and rulers. Each of the leader will gain perks which give bonus(negative or positive) on task they are performing. Leaders have limited life span and they will die for old age, but new ones can be replace the old one. Some rulers can have heirs which will eventually replace parents. These leaders can have also internal power struggles in certain government types.
The history

After a game players are given a quick overview of major galactic events and how other realms did during the game. There will be also history events of all major events that leaders did during their time in the game.
The story

When you start the game, background story will be generated for your realm. At the end of the game you can see your realm's full story. There is also possible to see other realms' stories.
Features
- Randomized galaxy with three different starting placements
- 17 different space races to play
- 22 different government types to play
- 17 different starting scenarios where to start
- Any realm can start as an elder realm even human player
- Custom space races with editor
- Custom governments with editor
- Random events
- Planetary events
- Space anomalies
- Space pirates
- Privateering, trade fleets are actual ships which can be privateered
- Possibility to steal other ships with tractor beam
- Possibility to tame space monster with tractor beam
- Diplomatic relations between realms (War, Peace, Trade war, Trade Alliance, Defensive Pact and Alliance)
- AI remembers how it has been treated and will treat others accordingly
- Possibility to have casus belli against realm which have treated your realm wrongly
- Galactic Olympics to influence to other realms
- Technology can be traded in diplomatic trades
- If two realms are in alliance they won the game together.
- Possibility to fake military power in the galactic news (Can be lower or higher)
- Espionage ships and espionage missions with leaders
- Leaders acting as rulers, governors and commanders
- 6 Different technology branches each with 10 levels
- Each new technology will give either new ship component, ship hull or planetary improvement or new option for espionage missions.
- All ships are designed based on currently available technology
- AI does not cheat and each AI is trying to make their own realm as strong as possible
- If two realms are in alliance they win the game together.
- Multiple ways to win the game:
- Military victory, Conquer over half of home worlds
- Diplomatic victory, Win diplomatic voting for Secretary of Galaxy
- Cultural victory, gain most culture and spread it over the galaxy
- Science victory, build planet with highest technological achievements
- Population victory, At least half of the whole galaxy population is yours
- Ascension victory, Find your way to ascend your space race into higher being
- Score victory, Have most of the score at end of the game
- 3 Difficulty levels to choose for each AI realm.
- Turn based space combat
- Planets can conquered with troops and bombs
- Direct support for Philips Hue RGB lights
| Status | In development |
| Platforms | Windows, macOS, Linux |
| Rating | Rated 4.7 out of 5 stars (6 total ratings) |
| Author | Reemax |
| Genre | Strategy |
| Tags | 4X, Sci-fi, Space, Turn-Based Combat, Turn-based Strategy |
| Code license | GNU General Public License v2.0 (GPL) |
| Asset license | Creative Commons Attribution_ShareAlike v4.0 International |
| Average session | A few hours |
| Languages | English |
| Inputs | Keyboard, Mouse |
| Accessibility | Interactive tutorial |
| Links | Source code, DevBlog |
Download
Install instructions
Download Open-Realm-of-Stars-0.24.0Beta-pack.zip and unzip the zip file. Then double click Open-Realm-of-Stars-0.24.0Beta.jar and it should be running if you have Java installed on your machine. If you do not have Java installed you can download it from here: Adopt OpenJDK
If you want to run Open Realm of Stars from command line run it with following command:
java -jar Open-Realm-of-Stars-0.24.0Beta.jar
Development log
- Open Realm of Stars 0.28.0Nov 15, 2025
- Open Realm of Stars 0.27.0Feb 12, 2025
- Open Realm of Stars 0.26.0May 18, 2024
- Open Realm of Stars 0.25.0Dec 10, 2023
- Open Realm of Stars 0.24.0BetaAug 01, 2023
- Open Realm of Stars 0.23.0BetaMar 02, 2023
- Open Realm of Stars 0.22.0BetaAug 13, 2022
- Open Realm of Stars 0.21.0BetaApr 06, 2022



Comments
Log in with itch.io to leave a comment.
I like how all the good games are ported anywhere BUT android . Looks like another nice game is yet unavailable for millions of Android users
I actually thought about porting to Android at some point, but since Open Realm of Stars uses Swing which is not available for Android, it would require redo whole UI and that would be massive work.
hi yeh got the jar files open game just get white screen....i have java platform se binary and open jdk platform binary tried both still with white screen thx
Sorry for late answer. Could you run it from command prompt or terminal? And give possible error message here in reply. It might be that it is not finding all the files or is not able to create the files/directories and therefore it is shows the white screen.
hi just downloaded game but cant find the jar file thx
Did you unzip the zip file and there is folder which contains three jar files. Game is Open-Realm-of-Stars-0.28.2.jar.
do you ever plan to add local multiplayer
Open Realm of Stars is never designed to have multiplayer, so adding that later is quite impossible. Biggest difficulties are combat and diplomacy.
In local multiplayer combat probably could work, but diplomacy would be still difficult to do or it would need to be different kind.
Is there a way to hide certain categories from event log? Like I don't wanna have to go through several pages of idle leaders or ships before getting to actual useful information.
No but I can make this feature request and add it to next release.
i created a wrapper/self containment for this game to start it will opengl true and run on windows without the need to install java on your pc.
It would be good to bundle it with the game... Sing out if anyone wants it.
Quick tip ya'll, if the game doesn't run too well (on windows, haven't tried through linux), your PC is probably defaulting to software rendering, which sucks, just add a "-Dsun.java2d.opengl=True" between "java" and "-jar" when running the game through command prompt, should fix everything 👍
You can also enable it from options: OpenGL hardware acceleration. When this is enabled restart is required. I have now seen one or two computers where it possible does not work so that's why it is not ON by default. If game does not start after enabling it. You need to modify or delete file .oros/oros.cfg from your home directory.
So I had OpenGL hardware acceleration on from the in-game option and it only partially worked, was still laggy, but this method full worked, so unsure of what's going on there.
Ohhh, this looks lovely.
Thanks
What's the minimum version of Java needed for this? I got a JNI error but I thought I was up-to-date...
Edit: I might not have been up-to-date... my installation was having issues. Uninstall Java and reinstalled from new. Now I get a "Java exception occurred" box and that's it... no additional information I know about... anything you can suggest I try? (The box is from the Java Launcher if that makes a difference...)
Java11 is minimum Java version. On Linux it is possible to install only java-headless which means it does not have GUI support and that does not work. Have you tried running it with command "java -jar Open-Realm-of-Stars-0.27.0.jar" from command prompt or terminal? It should show more info on Java exception occurred. Do you see any stack traces?
I'm using Windows 10... it seems that despite trying to get the newest version of Java I ended up with version 8... maybe Windows' fault due to its version? I don't know. I'll try and find time to troubleshoot (more uninstalls probably) but it looks like the problem is squarely at my end (the error message given said it could only run packages up to version 52 but this game was packaged with version 55).
Apologies for the trouble.
Is there a way to start a game with no AI to test game features?
There needs to be at least one AI realm. What do you mean by test game features? If you want to try out game that you do not encounter AI, best possible is pick largest map 256x256 with two realms and pick starting position "Elders at middle". Now AI Realm would be at other side of the galaxy about 220 sectors away. Which takes approximately with starting engines about 70 star years to get there
Eh, I just used the species and government editor to give the AI the worst traits possible and gave them doomed planet start. Now they may as well not even exist.
Also is there a way to disable score victory entirely? Outside of file editing it to 999999999 years or something.
Victory score is always enabled, but you can change it how many star years it requires to happen. Longest time is 1000 star years aka turns. Which is a lot.
Hello and thanks in advance.
Is it possible to delete games or save files? I can't find how.
Not from the game itself. Save files are in your homefolder .oros/saves folder. But I could add button to delete save games, if that would be handy.
Thanks
Looks great!
Just found out about this game because of the art you've published on opengameart.org. Looks fun! Can't wait to play it.
I also love how you're still updating this game. That's pretty cool! Now if only I could have that same level of commitment rofl
Looks interesting.
Too early for me, but I'll stay tuned.
Wish you well in your endeavour.