Along the way, Abu Sha'aban picked up a Beirut university law degree. He also plays a mean game of chess. His latest adversary is Private Gilead Engel, a lanky 18-year-old Israeli national serviceman who sports the knitted skullcap associated with right-wing settlers. The score so far: Palestine 2, Israel 1. "It isn't easy to beat him," Abu Sha'aban concedes. "He's very good, very tough."
The two chess enthusiasts are based together in a cluster of white caravans surrounded by razor wire on a bleak hilltop south of Hebron, where Israeli and Palestinian security forces have surprised a sceptical world by keeping the peace for a full month since Israeli troops withdrew from 80 per cent of this incendiary West Bank city.
Mr Sha'aban is legal adviser to the local Palestinian commander. Mr Engel is the Israeli media liaison at the district co-ordinating office.
The two sides of the shared headquarters are divided by a wire fence. But the gate between them is more often open than closed. Now they drink coffee together and even play volleyball across the wire.
It has not always been so relaxed. "The first time I sat playing chess on the Palestinian side," Mr Engel said, "I found myself surrounded by 10 Arabs with Kalashnikov automatics. I was very afraid."
It is only four months since Israeli and Palestinian forces exchanged fire in Ramallah and Nablus, two cities handed over earlier to Palestinian rule. If the initial uncertainty has subsided in the Hebron base, it remained palpable on a joint patrol I accompanied through an outlying Palestinian neighbourhood.
Paramilitary Israeli border police and Palestinian police rode in separate jeeps. As the narrow road turned from asphalt to stones and rutted earth, the Israelis drew to one side and waved their Palestinian partners into the lead. Six weeks ago the border police were the hated enforcers of the occupation. They do not expect the Palestinians to forgive and forget quickly.
We stopped at Abu Sneineh, a rocky plateau overlooking the ancient, contentious centre of Hebron, a hill city sacred to Jews and Muslims. To the right was the massive shrine of the Patriarchs, where the warring faiths worship in sullen segregation. To the left was the Jewish quarter, home to 450 heavily guarded settlers. The joint patrol was there to make sure no vengeful Palestinian used the isolated site to snipe at the Jewish families down below.
"The Palestinian police have 15 checkpoints of their own to prevent demonstrations moving towards the Jewish enclave," the Israeli district commander explained. "We prevent Jewish demonstrations from our side.
"Every Palestinian police station has a rapid-response team, each with 16 men. On our side, soldiers have standing orders to stop any Israeli shooting at Palestinians. If necessary, they may open fire at him."
Asked if he fears a rerun of the gun battles between their forces, an Israeli paramilitary shrugged: "I just hope our Prime Minister [Benjamin Netanyahu] doesn't cock things up again." Hebron simmers, but for now at least the only contest is at the chess board.
n Jerusalem - Mr Netanyahu, warned by police about self-incrimination, has hired a lawyer to protect his interests in an investigation of alleged government corruption, Reuters reports. Yaakov Weinrot told Army Radio Mr Netanyahu hired him on Saturday: "He is certain the police will prove his innocence in this investigation."