blockchance on dagger?

Is this a crafted stat? I have been searching on poe trade with no result.

I found in a build a Sai dahher witj +6 to block chance. Where do I get it ?

ty

It's an implicit, either search for that or set 'Sai' basetype.

Sais are the Maraketh dagger. Maraketh gear always has a different implicit than what's considered "standard" for the base type. These are the Maraketh weapons by base type, as well as their implicits:

Note: Names given are the strongest variant of the three. Each has 2 lower variants too.

One Handed Axe: Runic Hatchet, 12% increased physical damage
Two Handed Axe: Fleshripper, 40% increased critical strike chance
Bow: Maraketh Bow, 6% increased movement speed
Claw: Gemini Claw, +14 Life and Mana gained per enemy hit
Dagger: Sai, 6% chance to block
One Handed Mace: Behemoth Mace, 6% increased attack speed
Sceptre: Sambar Sceptre, damage penetrates 2% of elemental resistances
Two Handed Mace: Coronal Maul, 6% increased radius of area skills
Staff: Eclipse Staff, 80% increased global critical strike chance
One Handed Sword: Tiger Hook, 3% chance to dodge attacks
One Handed Sword (thrusting): Dragoon Sword, 12% chance to cause bleeding on hit
Two Handed Sword: Exquisite Blade, 40% increased global critical strike multiplier
Wand: Profane Wand, 6% increased cast speed

You could farm a Sai at any area 68 or above (it's a lv70 base, so in a lv68 area only Rare/Unique mobs drop them).