Public festivals are commonly termed "matsuri", although this term has varied meanings—"festival," "worship," "celebration," "rite," or "prayer"—and no direct translation into English. Picken suggested that the festival was "the central act of Shinto worship" because Shinto was a "community- and family-based" religion. Most mark the seasons of the agricultural year and involve offerings being directed to the kami in thanks. According to a traditional lunar calendar, Shinto shrines should hold their festival celebrations on "hare-no-hi" or "clear" days", the days of the new, full, and half moons. Other days, known as "ke-no-hi", were generally avoided for festivities. However, since the late 20th century, many shines have held their festival celebrations on the Saturday or Sunday closest to the date so that fewer individuals will be working and will be able to attend. Many festivals are specific to particular shrines or regions. For instance, the Aoi Matsuri festival, held on 15 May to pray for an abundant grain harvest, takes place at shrines in Kyoto, while the Chichibu Yo-Matsuri takes place on 2–3 December in Chichibu.