קניין סודר acquiring by means of handkerchief as far as I can tell in the Raavad and the R''id (Yeshaya of Trany) seems to work because of a kind of acquiring by means of money.
With the Rambam it seems a different kind.
The Tosfot Ha'Rid right at the beginning of kidushin says if the handkerchief is worth more than a penny then the kidushin is valid.
[That must be how he understands the gemara there that "exchange'' would not work because it is valid even for less than a penny.]
However the Rambam understands that that type of acquiring would not work for kidushin nor for letting a slave go free.
That is based on the Gemara in Kidushin i think around pg 79. One fellow had a Hebrew maid servant and threw at her a vessel and said, "With this vessel you go free." That the Gemara there says is not valid. At first the thought it is not valid because of acquiring by means of a handkerchief. And in they end they decided it was because the vessel was owned by the owner.
So the Raavad in fact says that letting a slave go free by means of acquiring by handkerchief is valid. The Rambam says not.
So what I see here is the an argument about the handkerchief.
I admit this is the way it looks to me. From what I can see in Rav Shach's Avi Ezri, he seems to understand this sugia differently and I can not figure out what he is saying.
With the Rambam it seems a different kind.
The Tosfot Ha'Rid right at the beginning of kidushin says if the handkerchief is worth more than a penny then the kidushin is valid.
[That must be how he understands the gemara there that "exchange'' would not work because it is valid even for less than a penny.]
However the Rambam understands that that type of acquiring would not work for kidushin nor for letting a slave go free.
That is based on the Gemara in Kidushin i think around pg 79. One fellow had a Hebrew maid servant and threw at her a vessel and said, "With this vessel you go free." That the Gemara there says is not valid. At first the thought it is not valid because of acquiring by means of a handkerchief. And in they end they decided it was because the vessel was owned by the owner.
So the Raavad in fact says that letting a slave go free by means of acquiring by handkerchief is valid. The Rambam says not.
So what I see here is the an argument about the handkerchief.
I admit this is the way it looks to me. From what I can see in Rav Shach's Avi Ezri, he seems to understand this sugia differently and I can not figure out what he is saying.