How many Mesechtos are there in Seder Nezikin?

Daf Hashavua

Bava Basra 2a

How many Mesechtos are there in Seder Nezikin?

10 - 8 - 1   ?

R. Yosef said "כולה נזיקין חדא מסכת". R. Huna argues and considers them  as separate Mesechtos. (Bava Kama 102a)

There are important Halachic differences  if we count them as one or separate  Mesechtos. 

(אין סדר למשנה only applicable in same (1) Mesechta)

*Although the general rule is, we Pasken like R. Huna against R. Yosef, in this case, the Halacha (Rambam) is like R. Yosef being Rebbi named the three Mesechtos " Bava

Kama,Metzia & Basra". (gate 1,2,3 - one  Mesechta with 3 gates)

There is also a Machlokes Rishonim if Reb Yosef referred to, only  the first three Mesechtos

as Kulo Nezikin (Bava Kama Metzia Basra)

or all 10 Mesechtos are considered one.

1)   10     R. Huna 

2)     8     R. Yosef (Rambam Ritva)

3)     1     R. Yosef (Ri Migash**)

* Hakdama Tosfos Yom Tov

** The first Maharsha in Bava Basra seems to agree with the Ri Migash