[Apologies for diverting this thread into WW discussion, but....]
I don't think there is. THe key is whether or not you're fighting on your home territory or on foreign culture territory. (Or neutral land). If you're fighting at home, the people will rally to defend their homes even if you initiated the war. ON the other hand, if you're spending most of the time fighting overseas, WW will kick in even if someone else started the war.
Also be aware that your own WW rises massively if you USE nuclear weapons. WW also increases if you're nuked, but not as much if you're the one firing them off.
I also found it interesting that *winning* a battle overseas also increases WW, just not by as much if you lose! So that has implications for fighting a war of attrition....
A new war strategy I've implemented recently has been murderously effective at taking a civ from the front-runner in points, down to zero and in the dust.
Step 1) I build up, not the ARMY to conquer, but the ability to quickly switch to wartime production, always having at least 2 or 3 units queue-swapped into a city's build queue (which upgrade over time as new techs are discovered, without spending gold on the upgrades).
Step 2) I tempt the target civ into hating me by refusing all trades or making outrageous trade requests/demands, different religion, overall policy of antagonization. I further supplement that approach with keeping a bare minimum cadre of actual units holding cities.
Step 3) Over steps 1 and 2, I build up a decent stockpile of gold, minimum 2000.
Step 4) The target civ declares war on me and 90% of the time this involves a flood of cavalry into the rich border lands to take plunder.
Step 5) I mobilize the war machine and focus an entire first phase of the war on DEFENDING. Every cav unit that hops on my side of the border gets piked out of existence, and the pikes run back into the cities to heal. Several pikes per border city. Sometimes I'm able to supplement these by advanced cavalry units from slingshotting the liberalism discovery to Nationalism then Military Tradition. (In the build queue they go from horse archers to knights to cavalry.) When they bring stacks they get demolished by waves of catapults and obsolete units (advanced cavs finish them off).
Step 6) While step 5 is in progress, I gear up an offensive stack: roughly equal amounts of each type of unit, a little heavy on cavalry in the beginning to fend off waves of enemy catapults or cannons, and usually in the later phase, grenadiers (no, I'm not one of those whiz kids who's able to conquer the world before anyone can build macemen!)
Step 7) When the enemy advanced slows to a trickle of just one new cav invading each turn, and no new stacks in the past 3 turns, by about that time my offensive stack is built and ready for the advance. Each unit is top of the line, either newly-built or gold-promoted.
Step 8) Rather than be in an extreme rush to take cities, OR to plunder every last square, I find a good defensive siege position adjacent to their cities and wipe out the defenses to absolute zero, emphasis being on avoiding casualties of the siege-layers (always with at least 2 each of forest defenders or hilltop defenders, and a level III medical unit!)
Step 9) When defenses are at zero, heal everyone up prior to attacking--usually it also takes an extra turn or two to re-zero the defenses after the healing period.
Step 10) Start the city attack: First wave is the cats or cannons with the lowest experience, usually with a combo of city rader I and collateral damage upgrade. The cannons are cannon fodder, hehe. I've found that of all the non-AI units in the game, cannons can be the most lucky too in terms of beating enormous odds in a city attack. I've had odds on the order of 30:12 against my attack and still, not just be able to withdraw, but win the fight, with cannons. For some reason. Second wave is the more experienced artillery, but ONLY if the odds favor the attacks. If not, send in grenadiers to weaken or wipe out the defending gunpowder units. Overall for any class of unit that makes sense to attack with at any given time based on the strongest defending unit, I start with the most junior units so that if they lose, a campaign-long investment in building up experience isn't out the window. I only send in senior units if the odds CLEARLY FAVOR victory. Even if that only adds one point at a time, it's a low-risk point and continues the drive to that magical 17 XP, and the first unit to reach it gets "retired" to a rear area for low-risk defense only so that later on when it's time to build West Point, I'm able to do so. After I have that first 17 XP unit, the strategy is not quite as conservative and I'll be less hesitant to risk more-experienced units in a city raid.
Step 11) The city one-back from the city I'm attacking is a staging area for reinforcement mini-stacks, usually one cav and one grenadier escorting a cannon.
Step 12) City build strategy begins in the early phase with every city building units, and as new cities are taken, the new cities focus on CULTURE (so as not to lose the cities to high-culture neighbors). At the middle phase, when it becomes pretty much routine to take enemy cities at a clip, I start to select key rear-area cities to shift back to desperately-needed buildings (jails, universities in the science cities, banks in the shrine cities). Toward the end of the war it's down to JUST the high-production city supplying a trickle of new replacement units for any lost in late-phase sieges. This city builds Heroic Epic in the mid-phase of the war, and at the end of the war switches from unit production to West Point. By the time West Point is built, new modern eras have arrived requiring a new influx of more modern units, and a lot of the war-era stack will have to be deleted to make way for the new (only spending gold on upgrading veterans with promotion levels higher than what they'd be from the West Point city, and deleting the rest to keep unit upkeep costs to <10 GP/turn).
Step 13) The main goal is to have no cities from that AI civ remaining on the same continent as me. If that advance totally wipes them out, so be it. If they have colonies elsewhere, after the continent is completely mine, I begin to negotiate for peace, making demands for any techs they have, and often when they only have one colony city elsewhere they'll give up just about anything to put an end to the war--and then the bonus of those techs makes it worthwhile to have the unhappy penalty of "we wish to rejoin our fatherland"). On some rare occasions they have nothing to offer in exchange for peace and I have a good enough navy to be able to transport my stacks to their off-continent colony, and then I do so for the final wipe-out to get rid of the "fatherland" penalty. If my navy sucks I just eat the penalty and focus on rebuilding.
This probably has flaws in it, but most of the time on "continents" map type it gets me a large enough land mass that I finally get enough resources (oil, aluminum, heatlh-related) to be a major contender for the space race, and win space race about 4/5 of the time.
so if his 5 units kill your twenty, then they'll earn 4 experience points a piece, on the average. then he almost certainly gets some well-upgraded units.
Also, a longbow came out of nowhere and attacked Kyoto(I was Gandhi angains Toku)against a MECH INFANTRY with combat 3 and WON!
