There are both real time and turn based 4X, but all of them have one thing in common, the aforementioned 4 exes, specifically:
ExplorationExpansionExploitationExterminationThe first, Exploration, refers to starting on a completely foreign and unknown map and getting to explore it bit by bit.
The question is:
Can a 4X still be a part of the genre without this?
Surprisingly, the answer is yes, and it has been done before already.
I’ll present examples to back up such a claim.
First of all a pretty old -but incredibly fun and easy to get into turn based 4X – or rather 3X – Imperialism.
Imperialism offered you the ability to both play on a random world or our our very own Earth, but in any case, you knew the geography of the map and each great power’s position beforehand, so the game can be considered a 3X for argument’s sake.
Although there were minor instances of exploration, mainly sending geologists to search for valuables resources like iron gold or oil into your newly conquered territories.
The game is pretty old by now, 19 years old in facts, but it relying less on exploration and more on exploitation and, to an extent, on diplomacy made it a certainly peculiar example of what a 3X could possibly be.
Although such a formula was promptly dropped (in part) with Imperialism 2, where when you discover the new world it has a totally random shape and resource allocation, in contrast to europe that has fixed resources already discovered. In Imperialism 2 the new world played an important, but not crucial part, because for a control victory more than half of europe was needed and a european only game would have certainly been harder than one with support from colonies.
The conclusion is that while Exploration is a fundamental aspect of many 4X games and indeed contributes to the game’s feel and it’s longevity, it is not impossible to create a good 4x game without or at least with limited exploration.