It has good points, but it's still a definite "no". Don't watch this, because:
(a) it's a nudity-filled harem anime where almost all the girls are 14 years old and the 28-year-old male protagonist finds them sexy.
(b) the sleazy scenes are stupid enough to break the show. Whatever your threshold is for acceptable plausibility in trash, this show will fall short of it.
(c) if you're a sleazehound... come on, they're fourteen. (Admittedly they all have anime faces that don't really convey age, but the teens are clearly smaller than the adults.) You can do better than this.
Thought experiment! YOU are a dirty anime producer! (i.e. you produce dirty anime.) You want embarrassing filth! Your hero (Nobunaga) is a schoolteacher, so of course his tiny 14-year-old "wife" accompanies him to school and makes this announcement to his class. "I'll make something clear from the start. Nobunaga-sensei has already promised to marry me when I turn sixteen. I will be his wife! But I will allow you to be his concubines, so know your place."
Theoretically, that's funny. What's more, Nobunaga-sensei's reaction confirms her story. "What the hell are you doing, Kichou? I told you to keep your damn mouth shut!"
...and nothing happens. There are some comedy reaction shots, but then everything's back to normal again. There are no consequences. Nobunaga-sensei doesn't get fired, investigated or arrested. His outburst is unrealistic because it's a daft comedy reaction, ignoring how a human being would behave in that situation, i.e. damage limitation. Sincerely committing to this kind of curl-up-and-die comedy could have made this show terrifying (and hence hilarious)... but instead it's neutered itself. That scene kills all sense of danger. We're not afraid any more. We've learned, fatally, that the script's not taking itself seriously. It's just harem comedy nonsense that exists only for laughs and to please a scary target audience.
The premise is that our hero is the descendant and living embodiment of 16th century warlord Oda Nobunaga, i.e. Japan's most famous historical figure has become a loli-fancying worm who'll openly rant about how much he needs sex. (He's never had any, of course.) One day, Nobunaga-original's child bride, Kichou, falls through time to land in his arms! Their age difference was acceptable in 1549, but that was half a millennium ago. Nobunaga-sensei promises to look after Kichou, for a definition of "looking after" that includes making her play pornographic computer games. They're educational.
We later discover that Nobunaga-sensei can summon other long-dead figures who had unresolved sexual tension with him. In a way, this is clever. It solves the biggest plausibility problem of harem anime, i.e. "why him?". It also justifies outrageous smut, since the trigger is physical contact and so Nobunaga-sensei's hands on your boobs might awaken your personality from a past life.
Historically, it's surprisingly accurate. Nobunaga-original was indeed married to Kichou and we learn plenty of facts about her life, including unpleasant ones. (She never had any children and her brother killed her father.) Nobunaga-original did indeed have concubines called Onabe and Kitsuno (who died aged only 29). The most interesting development, though, is in the later episodes. Nobunaga-original was bisexual, preferring men. Extraordinarily, given its genre, this show embraces that too. (There's lots of Nobungaga anime, but this is the first I've seen mention that.) Admittedly it's being played for comedy (which is genuinely funny) and Nobunaga-sensei is loudly unhappy about it, but it's still surprising for a boobs-and-schoolgirls harem anime to give its hero some man-on-man action. Despite the show's many, many problems, I can respect that.
(There's even an in-joke that's not. The gender-bender character is called Ranma, for short, but that's not just a reference to the famous anime/manga. Nobunaga-original's attendant really was called Mori Ranmaru.)
For what it's worth, information you won't learn here is that Nobunaga-original had over a dozen concubines and at least 19 children. The latter he'd use as hostages, sending them to neighbouring lords who'd then sometimes kill the child and put its head on a stick. Nobunaga saw this as an excuse to retaliate. (His first famous act was the likely murder of his own brother, while later he'd massacre entire communities that opposed him, including women and children. Tens of thousands died on his orders.) He'd also rape his female servants.
When it's not being trashy, this show can be good. Kichou gets some character depth, especially in ep.4 when everyone visits Gifu castle and Kichou realises the painful truth. I liked the fact that there are at least three different ways of coming to the 21st century. (Kichou timeslipped as a teenager, Kitsuno's a flesh-ghost and can remember all 29 years of her original life and death, and other people were born and bred in the modern era but have a 16th century past life that's been waiting to awaken.)
Another good thing: Nobunaga-sensei has a younger sister and they have a normal, non-sexual relationship. It's distressing that I should have to say that, though.
The trash, though, is absurd.
1. Kichou's classroom declaration in ep.3 is a comic set-piece, but it depends on Nobunaga-sensei not having bothered to have a proper talk to Kichou about all this. (That's doubly glaring since he's a middle-school teacher and he should have been sacked twenty times over for professional misconduct during this series.)
2. "Whoever convinces sensei to have sex with him gets to marry him!" says a fourteen-year-old, to two other fourteen-year-olds. I don't think it works like that, Atsuka. Furthermore, the girls' plan is to lure Nobunaga-sensei into his classroom and have Mayu and Kichou strip in front of him. Are they expecting him to have sex with a fourteen-year-old, there and then, in his own classroom, in front of two other schoolgirls? It's nonsense. Human beings don't behave like that... but here they do. One moment Mayu's reacting like a sane person, then a few seconds later she's stripping.
3. Naturally, the scene ends with Nobunaga's hands on Mayu's breasts as another teacher walks into the classroom. Did you expect anything else? Nobunaga responds by pulling off the teacher's top, exposing her huge breasts and feeling inside her knickers, although it's possible that that scene was only in his imagination. (It's unclear.)
4. If someone falls on you, you'll hit the ground holding them from behind with your hands on their boobs.
5. Kitsuno calls herself a 29-year-old in a 14-year-old body. Nobunaga-sensei goes into lust raptures, openly celebrating in front of everyone at the prospect of a "legal loli". Yeah, right. That defence might not work as well as he thinks in court. (There is incidentally no reason for Kitsuno's body to be so young, except to pander to the story's fetish.)
6. When Nobunaga-sensei announces that he'll quit as a teacher, the girls talk him out of it. (Why? Would you want him teaching your daughter?) Mayu (the modest one) thinks she needs to be topless to speak. Apparently she's loved him ever since he saw her Boys' Love manga and responded with, "You're a great artist! Can you draw me something sexy, but with girls? Dick girls in dresses are fine with me, as long as they've got girls' heads!"
That was during the previous academic year, incidentally. Which is worse, (a) a teacher who'd say that to his thirteen-year-old student, or (b) the girl interpreting that as supportive and falling in love with him?
Even the censored version has boobs and nipples, by the way. Buxom-sensei gets hers out often. What's censored (and hence a selling point in the Japanese Blu-rays) is the under-age nudity.
This show can piss right off. I'd regularly be having that reaction. Admittedly there are interesting things about it and you couldn't possibly call it dull. However it's reprehensible, annoying and wilfully stupid, being nowhere near as good as the same author's Koe de Oshigoto!.
"Would you please fondle my breasts again?"