Proving forgery

Your query is like how to prove an adultery, thief, murder etc etc etc. Can any members of LCI answer such a broad question? Anyway, for your information, FSL report is not a Gospel truth that a judge would shut its eyes and relied on such evidence. In such a case much depends on the wisdom, experience and expertise of the presiding Judge and the depositions made by the expert.

What is the nature of the forgery? Is it due to additions / alternations made later? Is there a forgery of signature of another person? Proof of forgery depends on facts and circumstances of the case, including the nature of the forgery itself. You have not provided any such details.

Party X owes Rs 1 Lakh to Party Y, Party Y has promissory note for that amount, Party X denying the note and saying that it is forged. How to prove whether the promissory note is Genuine or forged.

Thanks!

thus x gave money or not is the big question 

but here you said that he is denying about only promissory note 

it may be written by y or signed by x and now he is denying to avoid paying money to y 

if there is any witness to the incident then that evidence is taken into consideration and if x says that even witness is also forged by y means the signature of x in the promissory note will be ascetained and send to the forensic lab to ascertain his signature and after getting the report the judge will ascertain wheater the report given by forensic lab is correct and the promissory note is genuine and will grant relief