Hidden Voices (season 1)

Under the versus format, both guest artists can eliminate one mystery singer each in the first two rounds, and then both can choose one mystery singer each to duet-perform with in the third round.

The winning condition implies to each mystery singer chosen by guest artist that has been duet-performed separately, if:

• One guest artist had chosen a "good singer" and another one had chosen a "bad singer"; or
• Both two guest artists had chosen a "good singer" or a "bad singer".

Rewards

The guest artist(s) gets ₫50,000,000 ($2,200) (if one of them is a good singer); or ₫25,000,000 ($1,100) each (if both two of them are good singers). Both winning mystery singers also receive ₫10,000,000 ($450) each.[4]

There were seven individuals of mystery singers standing on the platform with its aliases to keep their identities concealed until its initial performance.[5]

Round 1: Singer's visual

The guest artist(s) have time to observe and examine each mystery singer based on their appearance. After this, they will play a muted video of each mystery singer that reveals only 0.3 seconds of their singing voice as an additional hint.

Round 2: Singer's lip-sync

Every mystery singer performs a lip-sync of a song. Good singers lip-sync to their own voice, while bad singers lip-sync to other's voices.

Round 3: Singer's verdict

The guest artist(s) must have then 30 seconds to make an interview to the remaining mystery singers before making the final decision, at which point is depending on every panelists' opinion and/or an audience's majority voting.