An animation created for the Amnesty International Death Penalty Statistics 2013 report. 'Death Sentences and executions in 2012.'

HAKAMADA Iwao is a dead man walking.

Believed to be death row's longest serving inmate, Hakamada has been waiting 45 years to die, 30 of which have been spent in solitary confinement.

Sentenced to death in 1968 over the murders of four people, the former boxer could literally die any day, but he won't know when.

In Japan, death row inmates don't know when their time is up.

If the prospect of death wasn't bad enough, Amnesty International claim the now 77-year-old may be innocent after reportedly being coerced and beaten into making a confession over the killings.

Amnesty claim the evidence used to convict him was not conclusive and that he was interrogated by police for up 14 hours a day for almost three weeks, without the presence of a lawyer.

One of the presiding judges at the time resigned soon after the trial, publicly stating that "the wrongful conviction of an innocent man was too much for his conscience".

Hakamada will learn this week whether a court will resume a retrial by the end of March.

This would be his last chance to be found innocent - something many on death row don't get.

If it fails, he will be taken from his cell at anytime and hanged. He won't know when.

Amnesty International said there were serious concerns for his mental state and the uncertainty of when the execution would occur was excruciating.

And while some may associate death row with Texas or the Middle East, the Asia Pacific region actually accounts for the highest number of executions in the world.

China alone accounts for thousands of executions, as does India, Japan and Pakistan.

And if you think death row inmates get a simple injection and go to sleep, think again.

Here are some of the ways death row inmates are put to death around the world.

IRAN - HANGING:

The Middle East nation sparked outrage among human rights groups around the world when it failed to properly execute convicted drug trafficker Alireza M.

The 37-year-old was pronounced dead by the attending doctor after hanging for 12 minutes from a noose suspended from a crane at a jail in northeast Iran in October.

But the next day, staff at the mortuary in the city of Bojnourd, where his shrouded body was taken, found he was still breathing after falling into a coma.

Iran initially said he would face execution again once he recovered but Justice Minister Mostafa Pour-Mohammadi announced that his life would be spared.

Iran has one of the highest rates of execution in the world, with more than 500 cases last year alone, according to Human Rights Watch.

INDONESIA - FIRING SQUAD

The prisoner is taken to a field in front of 12 gunmen, three of whose rifles are loaded with live ammunition - the other nine are loaded with blanks. The squad fires from a distance of between five and 10 metres.

The prisoner has the choice of standing or sitting and can decide whether to have their eyes covered by a blindfold or hood.

A single shot is fired from each rifle, carefully aimed at the chest. If that doesn't kill, the commander will fire a point-blank shot to the head. No family or witnesses are allowed.

Indonesia carried out its first execution in five years when Adami Wilson was put to death in March 2013. The 48-year-old Malawian national convicted for drug trafficking in 2004 was the first of five men executed last year.

VIETNAM - LETHAL INJECTION/FIRING SQUAD

Vietnam resumed using the death penalty in August 2013 after an 18-month spell of no executions.

Convicted for murder in 2010, Nguyen Anh Tuan was reportedly executed in the Ha Noi Police prison through lethal injection - becoming the first to be put to death in the country since January 2012.

The government was previously unable to execute any convicts since switching from firing squads to lethal injections in July 2011.

The EU imposed a ban on European companies selling the necessary chemicals to Vietnam as part of an effort to pressure the country into abolishing capital punishment, but this year, Vietnam announced it would produce its own chemicals.

Human rights groups say the move is disappointing given the government had previously said death by firing squad was inhumane.

There are currently 586 people on death row in the country, according to local media reports.

SAUDI - BEHEADINGS AND CRUCIFIXION

In this Middle Eastern nation, prisoners face a gruesome end.

Inmates are told to kneel and are then beheaded before their bodies are publicly crucified, along with the separated head, as a deterrent to other would-be criminals.

In May last year, five Yemeni men were beheaded and crucified and then pictures emerged on social media appearing to show five decapitated bodies hanging from a horizontal pole with their heads wrapped in bags.

The gory execution took place in front of the University of Jizan where students were taking exams.

Just a few months before, a Sri Lankan domestic worker, who was 17 when she allegedly killed an infant in her care, was beheaded. Rizana Nafeek had no access to lawyers and claimed she was forced to make a "confession" under duress.

USA - LETHAL INJECTION

Texas, which is the most-prolific death penalty state in the US, executed its 500th person in June last year since state-sanctioned killing resumed in 1977.

Kimberly McCarthy was given a single, lethal dose of pentobarbital, a barbiturate by prison officials and pronounced dead 20 minutes later.

Convicted of the gruesome slaying and robbery of her neighbour, McCarthy was found guilty of the 1997 killing when evidence at the punishment phase of her trial tied her to two similar murders a decade earlier.

McCarthy, 51, was the first woman executed in Texas in more than eight years and the fourth overall in the state, which executes the most people in the nation.

To date, the US remains one of the top five countries carrying out executions globally. While the death penalty is declining nationally in the USA, it is actually on the rise in Texas.

Ohio Murderer Dennis McGuire is due be executed tonight. Experts say he could be subjected to a terrifying death because an "experimental" technique will be used to kill him.

The 53-year-old, is at risk of suffering "air hunger" - a sensation which will cause him to experience terror as he strains to catch his breath - when he is executed using the combination of sedative midazolam and painkiller hydromorphone.

It is the first time this method has been used in the US state of Ohio, and its effects are unknown.

Amnesty International Australia spokeswoman Sara Saleh said those found responsible for crimes should be punished after a fair judicial process but this shouldn't involve the death penalty.

"Amnesty International opposes the death penalty in all cases without exception regardless of the nature of the crime, the characteristics of the offender or the method used by the state to kill the prisoner," she said.

"The death penalty violates the right to life and is the ultimate cruel, inhuman and degrading punishment."

Ms Saleh said there was no clear evidence the death penalty acted as a more effective deterrent than other forms of punishment.

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