This achievement is currently bugged in version 1.7.2 and will likely not get an official fix since support for the game was dropped.
However it can still be acquired with a workaround! (Tested on May 21st, 2023.)
In Steam, open the properties for this game. Then select the Beta tab and rollback to version 1.4.1.
The actual requirements for this achievement are fairly straightforward, since it just requires you to build a Grand Inspector's Palace.
This is the fifth and final level of the Inspector's Office building chain.
The only requirement for this building is a small city (level 4 settlement), from its third level onwards.
If you just want this achievement as quickly as possible, Sima Yong is a good choice.
- Pingyuan, his starting capital, will already be a level 3 settlement. This means you only need to upgrade it once.
- It also comes with a 'Patrols' building, which will reduce the cost of your government buildings by 10%.
- On top of that, this faction gives you a 25% construction cost reduction as long as you have an army garrisoned in the city. (This can be a lone general without retinue.)
- You can also get the Qiaoren Workforce reform at the start. This will save you a further 750 gold and 3 turns.
This means you only need to invest 11,250 gold and 12 turns (compared to 18,000 gold and 15 turns by default).
P.S.: Make sure to disable any mods you might have as they might cause issues while using an old version of the game.