As the technology used to wage warfare has advanced, all new weapons and tactics have risen to use them. In the process, previous methods become far less prominent, and often eventually disappear altogether. Most modern navies have all but abandoned battleships, and the only blades today's soldiers carry are knives.

But in the future... what if technology takes a sudden and (un?)expected turn? The advent of military-grade lasers and fire-control systems that are decidedly ''not'' PointDefenseless makes missiles useless and taking aircraft into battle suicidal. All those modern aircraft carriers and missile cruisers suddenly become obsolete, and the battleship is king of the seas once more. What if personal-scale DeflectorShields make swords and spears viable weapons again?

This occurs a lot in SpeculativeFiction, where some discovery or advance in science or technology has the net effect of rendering the last 20 to 200 years of military tactical development moot, forcing a return to the methods of an earlier time of warfare, often still with high-tech spins on the old gear. For example, if large close-combat weapons become viable again, they may develop {{Laser Blade}}s, {{Hot Blade}}s, or {{Vibroweapon}}s. This overlaps with RetroUpgrade.

See also BreakOutTheMuseumPiece, when this happens in a more immediate sense.


[[folder: Anime & Manga ]]

* In ''Manga/AttackOnTitan'', the military is primarily trained in [[DualWielding double swords]] and hand-to-hand combat because the unique biology of Titans makes projectile weapons nearly useless, though cannons still get used in Titan defense to slow them down and rifles are kept around to enforce the law and to deal with possible civil wars or uprisings.
* ''Anime/MobileSuitGundam'' introduced the Minovsky Particle, which when scattered across an area did a number on detection and guidance equipment, forcing both land and space combat back into visual ranges. It should be noted that the arming of the Zaku II with a [[HotBlade Heat]] [[AnAxeToGrind Hawk]] was something of a predictive move, with Zeonic designers figuring that the Federation would develop their own mobile suits sooner or later, and added the weapon just in case.
* ''Anime/MobileSuitGundamSEED'' has "Neutron Jammers", which prohibit fission reactions and jams radios. The result: no nukes, everything runs on batteries, and, you guessed it, close-range combat.


[[folder: Literature ]]

* ''Literature/CoDominium'': To keep the the status quo, the titular Soviet-American alliance has banned most research. While their SpaceNavy hasn't suffered (being needed to colonize and police the stars), the restrictions has caused a regression in ground combat. Improvements to computer countermeasures, railguns, and man-portable missiles have made aircraft obsolete. Improvements to body armor has limited effective sizes of ammunition. 21st Century warfare resembles early 20th century combat. In addition, the colonial worlds lack industry, so very few can build tanks or artillery. Unless it's a [=CD=] Marine outfit or a merc company from one of the richer planets, often battles on colonial worlds are infantry only.
* ''Literature/HammersSlammers'': Thanks to accurate targeting and Powerguns, aircraft has practically disappeared from the field of battle. Artillery fire can be interdicted by powergun blasts, but shells still manage to get through. Nukes are rendered useless thanks to "nuclear suppression fields". In the backstory, tanks themselves almost disappeared from the battlefield due to developments in technology -- man-portable anti-tank rockets, pin-point accurate missiles, and helicopters that could strike rapidly all made tanks rapidly obsolete until fusion and powerguns made them practical again.
--> "Technology had dragged the tank to the brink of abandonment. Not surprisingly, it was technology again which brought the panzers back."
* In the ''Literature/ChildeCycle's'' first book, ''Dorsai!'', long range countermeasures have actually reduced the effectiveness of many weapons. Civilians have better, more advanced firepower than most soldiers. As a result, many troopers rely on simple, effective weapons.
* ''Franchise/{{Dune}}'' has "Holtzman fields", which radically changes war. Artillery is obsoleted, most projectile weapons can't penetrate the field, and even lasguns can't be used due to "explosive pyrotechnics". As a result, ground combat is relegated to sword combat. The exception is found on the titular planet -- shields attract {{Sand Worm}}s, and as such can't be used for the most part, causing warfare on Arrakis (Dune) to shift back the other way. This spreads to the rest of the empire in ''Literature/GodEmperorOfDune'' when shield technology is banned.
* In the ''Literature/LegacyOfTheAldenata'', the invading Posleen have point-defense strong enough to neutralize our missiles and aircraft. Necessitating the revival of battleships on sea and "land ships" on land with a lot of armor and big guns.
* Impeller drive in the [[Literature/HonorHarrington Honorverse]] places an impenetrable field right above and below starships, meaning that ships can only be hit in two dimensions or conversely fire from those same sides, thus [[SpaceIsAnOcean broadsides in 3-d space]].
* In ''Literature/WorldWarZ'', the world's armies have largely abandoned tanks, jet fighters, aircraft carriers, and indeed most modern tactics, as such equipment and tactics are poorly suited for fighting masses of unarmed, NighInvulnerable zombies that can't feel pain or fear. While trucks and cargo planes are still invaluable for logistics, and armored infantry fighting vehicles like the Bradley are also useful for clearing out urban areas (where a massive horde of zombies can suddenly emerge from around a corner), assault rifles, grenades, and bayonets have been replaced -- the new weapons of choice for most soldiers are semi-automatic rifles and the "Lobotomizer", a cross between a shovel and a battleaxe. The squad is also no longer the base unit for organization of soldiers -- instead, they are organized into lines and fire in accurate, devastating salvos, like something off of a Napoleonic battlefield. More modern equipment is still kept in reserve for fighting rebels, separatists, survivalist holdouts, and enemy nations, but otherwise spends most of its time mothballed. Notably, Russia and China are among the few countries that stick with 'traditional' combat tactics and weapons in their fight against the zombies, and [[RussianGuySuffersMost both countries suffer massive casualties]] as a result; the Russians held together solely due to [[ChurchMilitant religious fervor]], while the Chinese almost fell apart entirely until the military brass launched a coup against [[TooDumbToLive the Communist Party leadership]] and turned things around.
* Played with in the ''Literature/BookOfTheNewSun''. Most of Urth's technology has regressed, so most soldiers are armed with crossbows and slings, while others have lances. Crossbows and slings that have pyrotechnic ammunition, and lances that can fire bolts of energy. The cavalry charge is much in evidence, although horses are extinct and their replacements run faster than a motor vehicle.
* On ''Literature/{{Starfist}}'', the creation of the "Straight Arrow" AntiVehicle missile is so effective at destroying tank warfare that the only person to think of bringing it back in any major warfare capacity in the ''hundreds'' of years afterwards is the bad-guy warlord of the book ''Steel Gauntlet'' (and ''this'' forces the Marines to BreakOutTheMuseumPiece themselves-namely, the knowledge on how to produce the missiles, as well as what few working models remain(ed)). Even then, warfare remains a business done purely by infantry, with ([[HollywoodTactics comparatively to modern day]]) ''very'' minor combined-arms (artillery, drone, [[DeathFromAbove orbital bombardment]] and APC) support.


[[folder: Live-Action TV ]]

* ''Series/DoctorWho'': "Genesis of The Daleks" shows Skaro, the home planet of the dread pepperpots, was undergoing this because of just how long the ForeverWar on that planet had been going. Both sides had started out with nukes and chemical weapons, and by the time the Doctor and crew arrive, the soldiers are fighting with guns or even bayonets, because they're running low on bullets by that point. The Doctor speculates that if they go any further, both sides will be forced down to bows and arrows.


[[folder: Tabletop Games ]]

* ''TabletopGame/MutantChronicles'': When the Dark Symmetry (a cosmic horror force) is released, advanced computers become evil and electronics become unreliable. As a result, warfare (and pretty much everything else) regresses to TheSeventies.
* In ''TabletopGame/{{Warhammer 40000}}'', though modern weaponry has not been replaced, melee combat is back again as regular fare on the battlefields with exclusively melee-range weapons being commonly deployed, but there is no single specific reason for this having happened (aside from the expected RuleOfCool of course) - the rulebook words it implying close-combat likely renders troops unable to shoot their guns despite PistolWhipping being perfectly usable to give yourself an opening to fire in a melee. However, many assault troops employ SwordAndGun to get something of a best of both worlds in close-combat, though there is certainly individual troops who use ''only'' melee weapons for arming themselves.
** And the fact that when you're a [[OurOrcsAreDifferent hulking monstrosity]], a [[OurElvesAreBetter psychic bullet-dodging alien]], or a [[OurDemonsAreDifferent daemon from Hell]], and your enemies are {{Puny Earthling}}s, close combat isn't that stupid of an idea. Likely expecting them to try it, the {{Puny Earthling}}s have BayonetYa as standard-issue though being {{Puny Earthling}}s against the aforementioned opponents, it doesn't especially help their odds when their enemies get close enough.
* The old ''TabletopGame/{{Manhunter}}'' universe had swordsmen who specialized in fighting aboard spacecraft, where guns are impractical because of the tendency of stray bullets to punch holes in the hull and/or destroy necessary equipment.
* In ''TabletopGame/BattleTech'', warfare is dominated by Battlemechs and lasers are commonly used weapons. However the first two Succession Wars have knocked back most Inner Sphere's technological progress resulting in most fights limited to close range combat. The Clans however possess more advanced technology than the IS but they intentionally made most of their fighting limited to honor duels, to hone their skills and limit their losses. One response to the appearance of the Clans in the Inner Sphere was for the latter to produce 'Mechs armed with melee weapons (Axes, Clubs and Swords). This being the extreme end of the idea of nullifying the range advantage of Clan weapons by fighting at close range.


[[folder: Video Games ]]

* ''VideoGame/CommandAndConquerTiberiumWars'' has GDI revert back to using tanks, since it was just more cost-effective. It turns out Mecha and [[HoverTank hover tanks]] are too expensive to maintain. Similarly, Nod ends up abandoning subterranean burrowing vehicles due to environmental changes.
* Averted in the ''VideoGame/DuneII'' and ''Videogame/EmperorBattleForDune'' games. Unlike the books (shield technology makes many projectile weapons obsolete), the various factions operate tanks, artillery, and machine guns just fine. ''Dune II'' has benefit of being set on Arrakis, where Shields are avoided to prevent the [[SandWorm major local wildlife]] from going berserk. But in ''Emperor'', all units are still usable even not on Dune, and House Ordos [[TooDumbToLive still]] uses some shielded units on Arrakis.
* In ''VideoGame/MetalGearRisingRevengeance'' CNT armour makes cyborg infantry nearly ImmuneToBullets, so melee {{Vibroweapon}}s have come back into fashion.
* Autonomous air defense systems have rendered things like drones and [=ICBMs=] useless in the future of ''VideoGame/CallOfDutyBlackOps3''. As such the demand for capable foot soldiers is once again on the rise and cybernetic augmentation is there to make them all the more effective, [[CyberneticsEatYourSoul albeit at a possible price]].
* ''VideoGame/DevilsThird'' is premised on the "Kessler Syndrome" theory: that is when man-made satellites in Earth orbit collide, the debris will begin a chain reaction that will destroy other satellites in sequence. In their world this has indeed happened, which forced the end of technologies such as GPS and satellite imagery and wars are fought without these advantages.
* In ''VideoGame/ArmoredCore'', the advent of powerful mecha - particularly the [[SuperPrototype NEXTs]] in the 4/For Answer continuity, have rendered close combat using {{Laser Blade}}s an extremely effective strategy, since such mecha are both very fast and extremely resistant to gunfire. Thus, a SwordFight between thirty-foot-high mecha moving at more than the speed of sound is not an uncommon sight on future battlefields, as a single strike from some of the more powerful {{Laser Blade}}s can be a OneHitKill.


[[folder: Webcomics ]]

* In the Big Head Press comic ''[[ Phoebus Krumm]]'', "S-fields" enable FTL travel but disable all electronics within the field, making space warfare essentially [[WoodenShipsAndIronMen age of sail]] [[SpaceIsAnOcean naval combat]].
* In the future of ''Webcomic/{{SSDD}}'' advances in anti-air defense had made air and missile strikes nearly impossible, and fullerene armor made ordinary guns obsolete. Which meant most battles were fought on the ground, by men in suits armor hitting one another with hammers. [[ "Oh, how far we have come."]] One of the major story arcs involves a war that ends when one side uses a KillSat to knock out their opponent's AA and launching a bunch of [[BreakOutTheMuseumPiece museum piece ICBMs]].


[[folder: Real Life ]]

* The aircraft carrier example given in the description is [[ speculated]] by some military theorists to be on its way to becoming TruthInTelevision sometime in the 21st century, due to the increasing efficacy of anti-ship missiles. Given that these same missiles can also sink other large boats, the consequence of this would be that the future of naval warfare in this environment would resemble a mix of the mid-late 19th century (before the [[LensmanArmsRace dreadnought race]]), with every surface vessel larger than a cruiser (the smallest warship that can operate independently in the open ocean) rendered obsolete, and the early 20th century, specifically the submarine warfare employed by Germany in [[UsefulNotes/WorldWarI the two]] UsefulNotes/{{World War|II}}s, albeit with the proliferation of much more powerful and long-ranged weaponry. Such predictions take on [[ an especially ominous tone]] for the United States, whose unmatched navy is built entirely around the power of its carrier task forces; the other boats in the fleet are all there to protect the carriers.
* Albert Einstein:
-->''"I know not with what weapons WorldWarIII will be fought, but [[AfterTheEnd World War IV will be fought with sticks and stones]]."''
* During UsefulNotes/WorldWarI, it was often said that the closest land-based comparison for aerial dogfighting was the combat of the Middle Ages, particularly the tales of knights dueling one another on even terms. This was seen as a positive thing, with many viewing aerial combat as the last bastion of [[WarIsGlorious martial chivalry]] in comparison to [[WarIsHell the horrors of industrial trench warfare on the ground]] (leaving aside the fact that pilots in World War I had [[ arguably higher casualty rates]], especially once air combat started picking up in 1917), and {{Ace Pilot}}s for both the Allied and Central Powers would later be romanticized in terms similar to those of medieval knights.
* During the UsefulNotes/EnglishCivilWar there were calls, especially on the Royalist side, to go back from Muskets to Bows and Arrows. There was a justification, it was difficult for gunpowder production to keep up with consumption and Muskets aren't that much more lethal. In the end though it wasn't practical because of the amount of time it takes to train an archer.