Title: Chaplet of the Divine Mercy
Content:  to a city to destroy it. Kowalska began to pray for God's mercy on the city and felt the strong presence of the Holy Trinity. After she prayed the internally instructed prayers, the angel was powerless to harm the city. In subsequent visions, Kowalska learned that the prayers she spoke were to be taught to all the people of the world. According to Roman Catholic tradition, the chaplet may be said at any time, but it is said especially on Divine Mercy Sunday and Fridays at 3:00 PM. The chaplet is prayed daily at the National Shrine of The Divine Mercy in Stockbridge, Massachusetts. In the Philippines, the opening portion 
Title: Chaplet of the Divine Mercy
Content:  This prayer opens each decade of the chaplet and is prayed on the single beads separating the decades where the Our Father is normally prayed:"Eternal Father, I offer you the Body and Blood, Soul and Divinity of Your Dearly Beloved Son, Our Lord, Jesus Christ, in atonement for our sins and those of the whole world."
Title: Chaplet of the Divine Mercy
Content:  This prayer is used after the Holy God to end the chaplet:"Eternal God, in whom mercy is endless and the treasury of compassion — inexhaustible, look kindly upon us and increase Your mercy in us, that in difficult moments we might not despair nor become despondent, but with great confidence submit ourselves to Your holy will, which is Love and Mercy itself."
Title: Chaplet of the Divine Mercy
Content:  In a novena, the chaplet is usually said each of the nine days from Good Friday to Divine Mercy Sunday. Pope John Paul II was instrumental in the formal establishment of the Divine Mercy devotion and acknowledged the efforts of the Marian Fathers in its promotion in a Papal Blessing in 2001, the 70th anniversary of the revelation of the Divine Mercy Message and Devotion. Although the prayers said on the beads of the rosary chain share specific similarities between the Chaplet of Divine Mercy and the Chaplet of Holy Wounds, these are distinct chaplets and were introduced over 20 years apart, one in Poland, the other in France.
Title: Chaplet of the Divine Mercy
Content:  This prayer, repeated 10 times in succession, forms the body of each decade of the chaplet, using the beads where the Hail Marys are normally recited:"For the sake of His sorrowful Passion, have mercy on us and on the whole world."
Title: Chaplet of the Divine Mercy
Content:  This prayer, repeated three times in succession, concludes the chaplet, recited where the Hail Holy Queen is normally prayed:"Holy God, Holy Mighty One, Holy Immortal One, have mercy on us and on the whole world."
Title: Chaplet of the Divine Mercy
Content:  This prayer, repeated three times in succession, is prayed still on the first large bead and may be used along with the first opening prayer to begin the chaplet:"O Blood and Water, which gushed forth from the Heart of Jesus as a fountain of Mercy for us, I trust in You!"
Title: Chaplet of the Divine Mercy
Content: The sign of the cross on the Crucifix; ; The optional first opening prayer on the first large bead; ; The optional second opening prayer, repeated three times, still on the first large bead; ; The Lord's Prayer on the first small bead; ; The Hail Mary on the second small bead; and ; The Apostles' Creed on the third small bead. The Eternal Father on the large bead, with a specific offering each decade; and ; The For the sake of His sorrowful Passion on each of the ten adjacent small beads, with other petitions for mercy, emphasizing the offering of the Body and Blood of Christ. The Holy God on the medallion; ; The optional closing prayer, still on the medallion; ; Any further intentions; and ; The sign of the cross. The chaplet is prayed on ordinary rosary beads that are also used to pray the Dominican Rosary. The structure of the chaplet is as follows: The chaplet is begun on the short strand of the rosary beads: The praying of the decades then follows, repeating this cycle for each: To conclude:
Title: Chaplet of the Divine Mercy
Content: 1) All mankind, in particular, all sinners. ; 2) Christian priests and the religious. ; 3) Devout and faithful Christian people. ; 4) Non-believers and ignorant who will become Christians ; 5) Christian heretics and schismatics. ; 6) Meek and humble of heart, and children. ; 7) People who especially venerate and glorify Christ's mercy. ; 8) The souls in Purgatory. ; 9) Lukewarm and indifferent. The chaplet may be repeated over a period of nine days as part of a novena. According to Kowalska's Diary, Jesus himself in a vision asked that the Divine Mercy Novena be prayed as a preparation for the Feast of the Divine Mercy, celebrated each year on first Sunday after Easter. The novena should begin on Good Friday. There is a prayer intention for specific group of people on each of the nine days. The novena intentions for each day are:
Title: Chaplet of the Divine Mercy
Content:  This prayer is prayed on the first large bead where the Our Father is normally prayed and may be used to begin the chaplet:"You expired, Jesus, but the source of life gushed forth for souls, and the ocean of mercy opened up for the whole world. O Fount of Life, unfathomable Divine Mercy, envelop the whole world and empty Yourself out upon us."

Question: when do you pray the chaplet of divine mercy?
Answer: Good Friday.