The ultimatum issued Monday morning by Gilad Shalit's captors caught the Israeli leadership off guard. Shin Bet (Israel Security Agency) chief Yuval Diskin had warned the previous day that the saga might end up lasting "weeks, even months" and everyone was surprised when it suddenly seemed that the Hamas was trying to bring matters to a head. Prime Minister Ehud Olmert hurriedly canceled a Kadima meeting to conduct consultations; Chief of General Staff Lt.-Gen. Dan Halutz didn't cancel his visit with the Shalit family but had to admit that he wasn't yet sure of the authenticity of the ultimatum. But in a couple of hours they had regained their bearings and an official statement was issued placing the blame on the Palestinian Authority and the Hamas government. Behind the tough response to the ultimatum, and the even more bellicose interviews given by ministers in the evening, lay the realization that this was just another round in the psychological warfare raging between the two sides. Out in the field, nothing seemed to have changed. The small expeditionary force that had moved early in the morning into the northern Gaza Strip, carried on slowly removing roadblocks leading to Beit Hanun and searching for more tunnels in full sight of the world media who had staked out a hilltop within Israeli territory, while the main military force remained parked in the field next to Kibbutz Mefalsim where it's been for over a week now. At a nearby artillery battery, large cranes were constructing a wall of concrete barriers, to protect the living quarters from the blast of the cannons. The soldiers manning the cannons, belonging to a unit based on the Lebanon border, said that it seemed they would be hanging around south for a while yet. On the tenth day of Cpl. Shilat's capture, both sides are trapped in precarious positions, like chess grandmasters in a long and drawn-out game, they are making small feints and provocations in the hope of tricking the enemy into a blunder or finding a small chink of light that will lead to a sudden victory. Israel is determined to get Shalit back alive without seeming to give in to terror, but at the same time has decided to use this opportunity to redress the balance with the Palestinians, prove that incursions into the strip are not sacrosanct and exact a price for the Kassam firings. The only problem is that using anything near to the full extent of the IDF's power in Gaza, will quite likely get Shalit killed. That's why the ground operations have been extremely limited and close to the fence, aerial and artillery bombardments of open ground or empty offices, and the main effort put into issuing an ever varying range of threats on what would happen to Hamas if Shalit is harmed. The hope is that by slowly increasing the temperature in the Gaza pressure cooker, the captors will be spooked into making a mistake and let slip the vital piece of intelligence on their exact location. At first they were flushed by the success of the Kerem Shalom attack last Sunday, but the Palestinians quickly realized that a live Israeli soldier might seem like a great asset, but also a huge liability. On the one hand, holding him will mean life in the strip becoming increasingly difficult and the Hamas gradually losing its ability to rule, but releasing him without exacting a heavy price from Israel will mean a total loss of credibility not only among the Palestinians but throughout the Arab world. That's why they've also played a waiting game up until now, sending out ambiguous messages through the Egyptians, and hoping that Israel puts a foot wrong or makes some kind of minor capitulation that can be construed as a gain. But the IDF has failed to oblige them by accidently killing more civilians, which would have placed more pressure on Israel, and has insisted on placing the blame on the PA and the political wing of Hamas without making any overtures in their direction. The ultimatum was a bold move, a Palestinian attempt to put Israel's king in "check" but the government has decided to call their bluff. It is not only due to the overall policy of not paying out to captors so as not to encourage more kidnappings, but is part of the current tactic of not allowing the other side to gain the upper hand in this clash of minds.