A man was slashed with a machete at a crossroads in what is believed to have been a targeted attack.
The 31-year-old victim was assaulted by a man who jumped out of a car at the junction of White Lee Road, Batley Road and Common Road, Heckmondwike , at around 2am on Sunday.
The victim, who received a serious arm injury, was taken to hospital but it is not believed his wound was life-threatening.
The scene was taped off on Sunday morning as police officers searched for evidence .
Investigating officer Det Insp George Bardell said: "We believe the victim was walking down the street when he was assaulted by an unknown suspect who got out of a vehicle.
"The motive is unclear although it appears to be a targeted attack as nothing was stolen .
"Striking someone with a machete is pretty serious so we would put out a general appeal for witnesses."
Anyone with information about the attack should contact Kirklees CID via 101.