Tensai Ouji no Akaji Kokka Saisei Jutsu

In both anime the mcs are surrounded by beautiful and strong girls and have to manage the kingdom financially in a fantasy world. But with the help of the girl he's most interested in and by making alliances with other regions, they also succeed in battles and the kingdoms recover. The main difference is that Genjitsu focuses more in the political/military/resources issues to save the kingdom and feels a little more serious whereas Tensai is more comedy oriented because the mc just wants to sell the kingdom and disappear but it doesn't go as he expected... Both anime are pretty close and good. 

both had MC that are ruling kingdom but are not kings one a provisional king have been isekai as a hero and hand the kingdom but not the title and and the other is the crown prince with a sick father how unable to govern. both kingdom are in trouble one due to small size and poor location and the other from a number of crises that lead to the hero summoning that isekai him in the first place both are genius that scheme and reacted to the schemes of others and a very protective of their family and throw cation tot he wind if they are threaten or insulted both have subordinate that are long suffer from one differing values and idea thanks to being isekai and the other from will hidden laziness and childish of the other difference one is a harem isekai the other a more traditional fantasy and Wein is also a combat prodigy where Souma not a fighter in the least  read more 

The same plot where it involves a guy who found himself conscripted into solving a country's financial woes, while one was able to do it by using his wits, one was just sooooo lucky that whatever he does always turns out to be right. 

Similarities: -MC getting drafted into getting a certain kingdom out of bad management. -The same girl having to be the MC's sidekick. -Same, situation where the MC has a lot in his hands. Dissimilarities Genijitsu Shugi -MC really has to use his wits to do what was expected of him. -MC's girl roamnce basically borders around being profession and having to like the MC. -MC has a potential harem. Tensai Ouji -MC hopes to simply just sell the kingdom a go, but it doesn't go the way he expects it. -MC's girl looks more like a loli that can kick ass. -MC's was basically homegrown. 

Both of the story have same kind of strength that is using their own knowledge to solve the country problem. Both of the MC is genius. 

So Basically a guy reforming a kingdom from the bottom to the top 

Both shows involve rebuilding a kingdom and have done a great job of showcasing that process so far. Would love to see more content on both shows :))  

In both Anime, The MC decides to use their own ingenious methods to assist the kingdom in reviving its ailing economy! 

Fantasy sword and magic world but more focused on the politics aspect. Not so OP MC but incredibly smart. Top waifu material.  

In many aspects Genious Prince is the improved version of Realist Hero, for instance: - GP relies on fewer narrative devices but it doesn't attempt to hide them, whereas RH spends lots of its time on, for instance, fanservice in disguise. - In both shows the MC gets instantly appointed to lead their nations, however GP makes it easy to accept and move on; whereas in RH it happens randomly and clogs the narration trying to justify it. - In RH magic plays a role to conveniently solve many issues; GP relies solely on the wits of the protagonist. - RH stresses on minor (at times tedious) details of the governance; GP almost exclusively focuses on the grand scheme of things. read more 

Both the animes have a similar plot but they take different approaches 

A young monarch employing genius strategies for betterment of the entrusted Kingdom?.. If, this aspect of Genjitsu Shugi Yuusha no Oukoku Saikenki [How a Realist Hero Rebuilt the Kingdom] catches your interest and you want to watch another similar one, Tensai Ouji no Akaji Kokka Saisei Jutsu [The Genius Prince's Guide to Raising a Nation Out of Debt] is my recommendation. Both have a regal setup, with the young sovereign overcoming various difficulties faced by his kingdom. There is politics, war, strategies, with mix of comedy and romance. Note: A major difference between the two is that the latter lacks the Isekai theme of the prior. 

Tensai is the only anime I've found that comes even close to capturing a similar essence to Alderamin on the Sky. The plots are not exactly similar, but the tone of the comedy and the underlying competence of the characters, the depth of the characters' relationships with each other, and the chaotic unknown of where their adventures will take them next...so refreshing. Another piece of media with a similar feel is the webcomic Girl Genius. 

Both shows are non iseaki war strategy anime with similar setting. Also, the protagonists are lazy geniuses with some sidekick/partner in a similar position. Alderamin on the Sky is a bit more serious and have a more interesting production. But The Genius Prince's Guide to Raising a Nation Out of Debt shows a lot of promise.