Hattori mentioned that what Ashirogi Muto's Manga lacked was Serious Comedy and tries to explain what it was and how to implement it in 22nd Episode in second Season. Ashirohgi Muto implemented it but it was hardly described how and also the concept of serious comedy is still unclear with me. Please help with some examples!
In episode 22 of season 2, Shuukan Shounen Janpu editors Hattori Akira and Miura Goro have a meeting with Mashiro Moritaka and Takagi Akito (the mangaka team known as Ashirogi Muto) to discuss what their next manga series will be like.
In this scene, Hattori gives the following explanation of 「シリアスの笑い」(shiriasu no warai [「笑い」 can be translated as "humor", "comedy", or "comic"; the literal meaning of the kanji is "laugh" but it is used to refer to comedy acts]):
Foremost, the mangaka Hiromaru Kazuya's series 『ラッコ11号』 (Rakko 11-gou = Otter #11) is given as the primary example. It has a serious, realistic setting. In one chapter, an otter was made fun of on TV, and then the main character (who is an otter himself) rammed a truck into the station building and pulled out the victim otter to rescue him from his oppressors. The storyline is dealing with serious themes (bullying, vengeance) and the tone is serious as well, but when the truck slams into the side of the building, Miura agreed with Hattori's assessment, and reported that it made him laugh. In other words, the reader of the chapter probably strongly wants the otters to get back at the humans, and the main character's very earnest, dramatic way of doing so induces a feeling of "Yessss!" so the reader ends up laughing (perhaps partly in relief, partly at the ludicrousness of an otter barreling into a building).
Hattori points out that Hiramaru was not doing 「笑いを取る」 (warai wo toru = trying to get a laugh). Mashiro concurs that 「いいえ、真剣に書いてると思います」(Iie, shinken ni kaiteru to omoimasu = No, I think he was really writing it in all seriousness/earnestness).
Hattori contrasts Hiramaru's「シリアスの笑い」 with Ashirogi Muto's prior gag manga series 『走れ!大発タント』(Hashire! Daihatsu Tanto = Run! Daihatsu Tanto), which was written with 「呆けて笑わそうと考えている」 (bokete warawasou to kangaetieru = the mind-set of dumbing-down to make people laugh) and Hattori deems it 「もったいない」 (mottainai = too bad/a waste). Rather than being enjoyable to write, that method made Takagi feel 「苦しかった」 (kurushikatta = it was painful) and made Mushiro feel 「あまり…」 (amari...[tanoshikunakatta] = it wasn't really [fun]).
Hattori also contrasts 「シリアスの笑い」 with Ashirogi Muto's prior series 『この世は金と知恵と見た目』 (Kono Yo ha Kane to Chie to Mitame = This World is All About Money and Intelligence and Appearance) and with Iwase Aiko and Niizuma Eiji's series 『+ NATURAL』, which are both categorized as 「シリアス」 (serious) but 「笑いが一切もない」 (warai ga issai mo nai = there's not a speck of humor [in them]). A 「シリアスの笑い」 would be received by readers as just as serious in tone as those series, yet manages to bring some irony or makes the reader lighten up for a moment.
Hattori explains that Ashirogi Muto's 「シリアスの笑い」 would combine 「高木くんが作る笑い」 (Takagi-kun ga tsukuru warai = the kind of humor Takagi-kun can create) with 「真城くんのシリアスの絵！」 (Mushiro-kun no shiriasu no e! = Mushiro-kun's serious artwork!), resulting in a 「シリアスの笑い」 that only Ashirogi Muto could pull off.
The manga that fulfills Hattori's description of 「シリアスの笑い」 is Ashirogi Muto's subsequently published series, 『PCP -完全犯罪党-』 (PCP -Kanzen Hanzai Tou- = Perfect Crime Party).