It seems to me that there are ambiguities but also subtle connections in documents. The first major issue which I think has bearing and relevance to all other issues is whether monetary documents are valid from the Torah as per the Rambam (Laws of Witnesses, chapter 3, law 4), or if they are valid only from the words of the scribes as per the Ramban [Nachmanides] and the Shach in Choshen Mishpat chapter 28. It seems this might have bearing on other questions, e.g., if after the document is signed and there is acquisition by exchange of a handkerchief kinyan sudar, if that automatically makes the borrower liable even if no money has been exchanged as per Rashi Bava Metzia page 13 side a. [Rav Shach shows that most rishunim disagree with this in laws of loans chapter 23 law 5]. On that same page in baava metzia , there is an argument between Rav Asi and Abayee if the witnesses on the document cause it to be already acquired by the lender? Abayee holds yes (and rabainu izhak decided this way in the Tur choeshen mishpar 39 law 13.) and rav asi says no (and the Rif decided thius way in bava metzia page 16 or page 9 in pages of the rif). Other issues come up which are unclear to me, for example the same statement of Rashi on that page and the Rosh who deals with that particular statement of Rashi. Also, if the witnesses on the document are considered already tested and checked in court. [This is derabanan according to the Rambam.] Also, it is unclear to me if this whole idea of witnesses on the document cause it to be valid means witnesses alone, or also with Kinyan Sudar. To the Rambam that is with kinyan sudar, and that the kinyan was stated in the document, but to Rashi it is without acquisition by exchange. And in what way does the argument between R Meir and R Elazar about what witnesses make a document valid: the ones signing? or the ones witnessing? To R Elazar they are the ones witnessing. There is also an argument between Rav Shach and Rav Chaim of Brisk about which documents in particular is the Rambam referring to when he says monetary documents are valid DeRabanan. To Reb Chaim, that means only documents of proof, not only that cause a kinyan like the sale of land. To Rav Shach, the Rambam means all monetary documents, and brings a few clear proofs of his position. [And you might ask if we hold the witnesses on the document are considered as having been checked in court then why check again when the lender asks to be paid back?] ---------------------הIt seems to me that there are ambiguities but also subtle connections in שטרs. The first major issue which I think has bearing and relevance to all other issues is whether monetary שטרs are valid דאורייתא, as per the רמב’’ם (Laws of Witnesses, chapter 3, law 4), or if they are valid only from the words of the scribes as per the רמב''ן and the ש''ך in חושן משפט chapter כ''ח. It seems this might have bearing on other questions, e.g., if after the שטר is signed and there is acquisition by exchange of a handkerchief קנין סודר, if that automatically makes the borrower liable even if no money has been exchanged as per רש’’י בבא מציעא דף י''ג side a. [רב שך shows that most ראשונים disagree with this in הלכות מלוה ולוה פרק ,כ''ג הלכה ה']. On that same page in בבא מציעא , there is an argument between רב אסי and אביי if the witnesses on the שטר cause it to be already acquired by the lender? אביי holds yes (and הר''י רבינו יצחק decided this way in the טור חושן משםט פרק ל''ט law י''ג.) and רב אסי says no (and the רי''ף decided thus in בבא מציעא page ט''ז or page ט inדפים of the רי''ף). Other issues come up which are unclear to me, for example the same statement of רש''י on that page and the רא''ש who deals with that particular statement of רש''י. Also, if the witnesses on the שטר are considered already tested and checked in court. [This is דרבנן according to the רמב’’ם.] Also, it is unclear to me if this whole idea of witnesses on the שטר cause it to be valid means witnesses alone, or also with קנין סודר. To the רמב’’ם that is with קנין סודר, and that the kinyan was stated in the שטר, but to רש’’י it is without acquisition by exchange. And in what way does the argument between ר' מאיר and ר' אלעזר about what witnesses make a שטר valid: the ones signing? or the ones witnessing? To ר' אלעזר they are the ones witnessing. There is also an argument between רב שך and רב חיים of בריסק about which שטרs in particular is the רמב’’ם referring to when he says monetary שטר are valid דרבנן. To רב חיים, that means only שטרs of proof, not only that cause a קמיין like the sale of land. To רב שך, the רמב’’ם means all monetary שטרות, and brings a few clear proofs of his position. [And you might ask if we hold the witnesses on the שטר are considered as having been checked in court, then why check again when the lender asks to be paid back?]---