From WikiPilipinas: The Hip 'n Free Philippine Encyclopedia
“Kalayaan”, Katipunan’s newsletter, was formed and distributed during the late 1800s to stir the masses’ yearning for freedom. It reached the provinces and so was able to become a vehicle to raise the revolution throughout the different parts of the Philippines.
 Establishment and Growth
Just when two new members of Katipunan, Francisco del Castillo and Candido Iban, won the lottery, they went on to buy a printing press for the organization. With this, Katipunan, as led by Emilio Jacinto (known as The Brains of the Katipunan), founded and edited their newsletter – named as “Kalayaan” – on January 18, 1896. He also took on the pseudonym ‘Dimasilaw’. They started off by printing 2,000 copies and have them distributed to various parts of the country.
The Katipuneros distributed copies throughout the Philippine provinces to inform the masses on their cause and to let them know how they can help the country. Through this advocacy, Katipunan inevitably grew its rank as a reputable organization fighting for the country’s freedom. Prior to the newsletter’s establishment, Katipunan only had 300 members, but once it reached the provinces it soon went up to 30,000.
Soon after, Spanish officials learned about Kalayaan and so before they could even seize the newsletter, the Katipuneros already destroyed their copies.
 Deceiving the Spaniards
To deceive the Spaniards, they made it appear that this newsletter was printed in Yokohama, Japan. They likewise made believe that the Japanese sympathize the Filipinos, and that Marcelo H. del Pilar served as the editor (who, in reality was in Madrid, Spain and was at the brink of death).
 First Issue’s Contents
Its maiden issue also contained what was thought of as del Pilar’s editorial – which in reality was written by Jacinto. It went on by greeting the people and wishing them independence and solidarity and that he offered his life for the Filipinos as a whole.
It likewise contained Valenzuela and Jacinto’s article “Catuiran,” describing the Spanish friars and civil guards’ maltreatment of a village lieutenant.
Andres Bonifacio’s poem, “Pag-Ibig sa Tinubuang Lupa,” was also published here. It depicted the oppression that Filipinos experienced at that time and persuaded the people to act on it and gain their freedom from the tyrants. The same goes with Jacinto’s Manifesto which also encourages Filipinos to free themselves from the Spaniards and revolt against Spain.
- “Emilio Jacinto Burial Site Historical Marker.” Explore.  (Accessed on October 24, 2011).
- “Emilio Jacinto – The Brains of the Katipunan.” Filipino Heritage.  (Accessed on October 24, 2011).
- “Satire Writing During the Spanish Era in the History of Philippine Journalism.” Chosenclick.  (Accessed on October 24, 2011).