On the eve of the 1956 Suez (Sinai) War, the Israeli army ordered a wartime curfew on Arab villages near the Green Line, the then de facto border with Jordanian-held territory. In the Central District ("Triangle"), Colonel Yissachar Shadmi altered the standard curfew hours for the twelve villages under his command and instructed battalion commanders to shoot on sight anyone violating it. Major Shmuel Malinki, commanding the Border Guard unit at Kafr Qasim, testified that when he raised the issue of villagers who would be unaware of the new curfew, Shadmi told him he wanted no "sentimentality" and no arrests. Malinki in turn ordered his men that anyone leaving their home during curfew should be shot, with no arrests to be made.
The new curfew took effect before roughly 400 villagers working outside Kafr Qasim in the fields could be informed. Between about 5:00 p.m. and 6:30 p.m. on 29 October 1956, a platoon led by Lieutenant Gabriel Dahan carried out nine separate shooting incidents against residents, including laborers and schoolchildren, returning home unaware of the curfew. The killings totaled 48 people: 19 men, 6 women, 10 teenage boys (14–17), 6 girls (12–15), and 7 young boys (8–13). Survivor Jamal Farij described being fired on after being told his group's identity cards were not needed. One of the soldiers involved, Shalom Ofer, later said the unit "acted like Germans, automatically," without expressing remorse. The wounded went unattended for hours under the 24-hour curfew, and the dead were buried in a mass grave with the help of laborers brought from a neighboring village. In other villages under Shadmi's jurisdiction, no killings occurred because some local commanders refused to carry out the shoot-on-sight order.
Israel's military censor initially barred press coverage; word spread only after two Knesset members entered the village weeks later, and a media blackout was not lifted for roughly two months. Eleven Border Police officers and soldiers were court-martialed for murder before Judge Benjamin Halevy. On 16 October 1958, eight were convicted and sentenced to prison terms of seven to 17 years; Malinki received 17 years and Dahan 15. Shadmi, tried separately, was acquitted of murder and convicted only of exceeding his authority in extending the curfew, receiving a symbolic fine of 10 prutot. On appeal, sentences were reduced, then further reduced by the Chief of Staff, and finally curtailed by presidential pardon and remission; all convicted persons were released by November 1959. Malinki was later placed in charge of security at the Negev Nuclear Research Center, and Dahan was placed in charge of "Arab Affairs" in Ramla.
The trial produced Judge Halevy's widely cited "black flag" standard for when soldiers must disobey manifestly illegal orders. Documents released after a 2022 legal fight, including a secret trial transcript, described a reported plan referred to as Operation Hafarperet, said to have contemplated pushing Kafr Qasim residents across the border into Jordanian-held territory. In December 2007, President Shimon Peres formally apologized to the village. In October 2021, a Knesset bill to officially recognize the massacre was defeated 93–12.