Is the "you control" portion of "You may play this character as an attachment on a character you control," an ongoing check, or just a restriction when playing the card?
If you no longer control the character (eg. Blackmail) will Serene Ise Zumi be discarded?

Just now, Bayushi Shunsuke said:

Is the "you control" portion of "You may play this character as an attachment on a character you control," an ongoing check, or just a restriction when playing the card?
If you no longer control the character (eg. Blackmail) will Serene Ise Zumi be discarded?

The “you control” part of that line of text only applies when playing the character. If you lose control of the character while Serene Ise Zumi is attached to it, the monk will stay attached.

[Tyler Parrott, Mar 11 2020]

If you play Serene Ise Zumi as an attachment, then you use Togashi Hoshi to turn it into a character does it still not have the sincerity?

Just now, Bayushi Shunsuke said:

If you play Serene Ise Zumi as an attachment, then you use Togashi Hoshi to turn it into a character does it still not have the sincerity?

Serene Ise Zumi will not regain sincerity if Hoshi turns her back into a character, as her text caused her to lose the keyword when she was played as an attachment.

[Tyler Parrott, Mar 3 2020]