Identification of ancient Chinese knife coins [solved]

I need help with the identification of these ancient Chinese coins
1; from point to ‘handle’: 140mm, weight: 28g

2; from tip to ‘handle’: 161mm, weight: 44.5g

3; from tip to ‘handle’: 135mm, weight: 26g

4; from tip to handle : 141mm, weight: 29g

5; from tip to handle: 137mm, weight: 29g

Hello
Nothing on the reverse?(obverse) sorry for my english
patina look strange for me

they originally came with a thin layer of blue dust but that came of on my fingers when holding.
Here are the reverses:

1:

2:

3:

4:

5:

With the patina blach is a natural tarnish colour of bronze and blue dust is an effect of bronze disease.

Really not an expert of the knife coins But a patina of 2500 Years should not go away so easely
Price is Also a good indication to know if genuine

Quote: "....."​With the patina blach is a natural tarnish colour of bronze and blue dust is an effect of bronze disease.

​yes but stick on the coin
Waiting for another return

the four "is " this one
https://fr.numista.com/catalogue/pieces272807.html
didn't find the reverse of your coin
weight and dimension are not good
the perfect shape of the hole is also a good way to say that is not genuine
as you can see here