Tenshi no 3P!, Ryuuou no Oshigoto! Recommendations
These two series are not only almost similar in their premise and characters, they are also adapted by the same studio, therefore, those who enjoyed the first show, definitely will like the second.
Both are about a somewhat bland high-school protagonist coaching little girls in music and shogi, respectively.
If cute lolis who are insanely overpowered in their trade is your thing, enjoy!
Beware of sexualised children (no surprise though, this is anime after all).
Same stuff!. Harem with little girls. Almost identical animation.
Both anime have a mentor/student relationship between a teenage boy and younger girls.