It is an official 'Independence Day' tournament. It notes that it was in the 'Swiss system' but in fact describes it as, first 20 people playing under the 'loser is out' principle and the remaining five 'played against each other' -- a mixed "playoff" / league system, in other words.
The same correspondent noted that the tournament was announced in the same paper on April 28th, 1950, p. 31, with the note, inter alia, that "the Hadera [Chess] club published nice posters to advertise the tournament'.
The prizes were (some information about the books added using interent search and not found in the original article):
First prize: 'In the Battle' by David Ben Gurion, in five volumes -- about the War of Independence (1947-1949).
Second: 'Secret Defenders' [Magen Ba'Seter] by Zerubavel Gilad [ph. spelling] about the actions of the Palestinian [Jewish] underground warriors in Europe during WWII.
Third: 'A Nation at War' by Imanuel Ha'Deni [ph. spelling] about Jewish until in battles from WWI to WWII.
Fourth prize: a chess set.
It is notable that, as befitting the times, just after the war of independence, and the occasion -- a tournament to commemorate Israel's second independence day, the books all dealt with Israeli, or Jewish, military events. Still, it is true that at the time there were very few chess books in Hebrew.