One of the stamps showcases the terracotta model of a boat excavated from Lothal port, superimposed on engravings of the sailing ship of an Indus seal dating back to 2400-1900 BC. The other stamp depicts Kanhoji Angre's fleet of ships taken from a 17th century painting. An imprint of a lead coin of the 2nd century, showing a double-masted sailing vessel on both stamps, manifests the antiquity of India's maritime heritage.

Similarly, the first day cover has an interesting illustration of a stone sculpture of Borobudur, highlighting adventurous spirit of Indian mariners, who settled in the Javanese islands in the 8th century. Paintings from the Ajanta caves, travelogues of Chinese pilgrims, ancient Sanskrit literature, historical references to the wars of the Chola kings, and the establishment of a naval base in the Andaman & Nicobarislands in the 11th century manifest advanced ship-making technology.

Pulak Gupta, secretary of the Philatelic Association, praises the maritime heritage stamps. ``As part of the universal celebration in the year of oceanography, the release of this set of stamps has a special relevance,'' he says. Plus, the design and theme are good, he says. And the stamps can be collected under various heads: ships, water, heritage, coins.

The other release of the month is on the tercentenary celebrations of the Khalsa. India is not the only country that has brought out a commemorative stamp on 300 years of the Sikh religion. The Canadian Post has also issued a special stamp, says Gupta. The stamp can be collected under the themes of religion and temples, he adds.