The coroner Darren Salter began the inquest by offering his condolences to the families of the soldiers who were killed.
He said that the proceedings could not change the families' loss, but it could answer their questions and bring some measure of closure.
He revealed that he had inspected the Warrior vehicle in which the soldiers died, at an army barracks yesterday.
The families of six soldiers killed in an explosion in Afghanistan have arrived at the inquest into their deaths.
Five soldiers from the 3rd Battalion the Yorkshire Regiment and another who was seconded to the regiment died when their Warrior infantry fighting vehicle was destroyed by an improvised explosive device in Helmand Province in March 2012.
The families of Sergeant Nigel Coupe, Corporal Jake Hartley, Private Anthony Frampton, Private Christopher Kershaw, Private Daniel Wade and Private Daniel Wilford, are in Oxford for the hearing which is expected to last two days.
An inquest is being held today into the deaths of six soldiers, five from the Yorkshire Regiment, killed in Helmand Province in March last year. It was the worst single attack on British Forces in Afghanistan.
The soldiers were in an armoured Warrior vehicle hit by a bomb - the youngest was just 19. The inquest, in Oxford, is due to last two days.
A coroner has ruled that two Yorkshire soldiers gunned down by a rogue Afghan policeman inside their checkpoint were unlawfully killed.
But Oxfordshire Assistant Coroner Alison Thompson said that, although there was no apparent motive for the man opening fire on British troops, killing Sergeant Gareth Thursby, 29, and Private Thomas Wroe, 18, there was no established link between him and the insurgency in Afghanistan.
An inquest at Oxford Coroner's Court heard that both men died of multiple gunshot wounds after the man, a member of the Afghan Local Police, opened fire on them at a checkpoint in Helmand Province on September 15 last year. Recording a verdict of unlawful killing for both men, Ms Thompson said:
It is often difficult if not impossible to establish motivation in this sort of case, making it especially hard for families to come to terms with the death. And I am sorry that I am not going to be in a position today to provide a reason for this appalling attack as I have heard no evidence as to why it took place and therefore it would be wrong and improper for me to speculate in any way.
An inquest into the death of two soldiers from the Yorkshire Regiment has heard how the rogue Afghan policeman who gunned them down was not considered a threat.
Instead the man who opened fire on Sergeant Gareth Thursby from Skipton and Private Thomas Wrote from Huddersfield was "pro-ISAF" and a "real champion of the partnership" with coalition forces, the inquest in Oxford has been told.
The inquest heard how the Afghan local policeman, who was visiting from another checkpoint, opened fire on the men at the checkpoint known as Tora, in Nahr-e Saraj.
Sgt Thursby, 29, and Private Wroe, 18, were shot at checkpoint in Helmand Province on September 15 last year. The deaths came in a spate of "green-on-blue" attacks, in which Afghans appeared to turn on their British counterparts, in the latter part of last year.
Platoon commander Lieutenant Callum Cameron said Afghan Local Policemen (ALP) were based at checkpoint Tora with British troops, living, working and socialising with them each day. He said the Afghan man who opened fire that day was based at a nearby checkpoint but was well known in the area.
Both Sgt Thursby and Pte Wroe were seriously injured, with their comrades battling to save their lives. They were evacuated by helicopter but did not survive. Lieutenant Cameron said it was a shock that the man had turned on his coalition partners, and could not explain what might have caused it.
The inquest is due to start into the deaths of two soldiers from the 3rd Battalion The Yorkshire Regiment in Afghanistan. It's nearly a year since Sergeant Gareth Thursby and Private Thomas Wroe were killed by a rogue Afghan policeman at a checkpoint in Helmand Province.
Brian Kershaw lost his son in Afghanistan a year ago today. He was one of six soldiers from the Third Battalion The Yorkshire Regiment , whose deaths remain the biggest single loss of life in the conflict
Brian decided to mark the anniversary by sharing his thoughts in an open letter to his 19-year-old son.
As part of a major restructuring of the Yorkshire Regiment, the 3rd Battalion (Duke of Wellington) Regiment, which has its roots in Halifax, will be axed.
The decision comes after the Government said the regiment must reduce by one battalion, leaving only two, which will simply be known as the 1st and 2nd battalions.