On a cold February morning in Tokyo several years ago, I watched as a few dozen women, some young and many older, gathered at the Sensoji Temple in Asakusa to pay their respects and offer prayers. Contrary to expectations, the atmosphere at this memorial service was not at all sombre – no dark clothes for mourning; each of the attendees was clad in an exquisite, beautifully coloured kimono. The mood seemed respectful, but almost jovial. The ladies – seamstresses and embroiderers– had turned out not to farewell an old friend, but the used and broken tools of their trade: bent needles and pins, ready to be retired after months of faithful service.

I was witnessing the annual practice of hari-kuyo, the “memorial service for needles”; a quirky Japanese festival which has been celebrated for about four hundred years. I had read about the festival a week beforehand, in the Japan National Tourist Organization’s monthly list of festivals and events; having missed fude-kuyo – a similar memorial service for used writing instruments, such as brushes and pencils – only weeks earlier, I had decided that hari-kuyo was a must-see.

Kuyo – a Japanese translation of the Sanskrit puja – is a Buddhist rite of ceremonial prayer or offering, to calm and honour the spirits of the deceased. With or without religious overtones, kuyo is a particularly significant part of spiritual culture in Japan, where the Buddhist aspects of kuyo blend with traditional Shinto animist beliefs, according to which all things – both living beings and inanimate objects – possess a soul and spirit; hence the respectful repose of many thousands of used needles and pins.

There are various ideas on the origin of hari-kuyo. According to one theory, it is thought to have originated in a similar Chinese practice, which was introduced to Japan and spread from Awashima Shrine in Wakayama. Awashima Shrine is, to this day, famous in Japan for harikuyo. Another legend from northern Japan tells of a woman who was bullied by her daughter-in-law, and threw herself into the sea on after being falsely accused of having stolen some needles. Today, in some households where there is a daughter who does needlework, no sewing will be done if the sea has been rough the day before, and a form of kuyo will be performed instead.

On the day of the memorial service – 8 February throughout most of Japan, but 8 December in much of the Kansai region and western Japan – seamstresses and embroiderers take a day of rest from their craft, and bring their used, bent and broken needles and pins to their temple or shrine. As they pay their respects, their needles and pins are stuck upright into blocks of tofu or konnyaku (a kind of edible jelly made from a plant-based flour). Tofu and konnyaku are used because of their soft texture; which is thought to soothe the needles after their labour, effectively wrapping them with tenderness and gratitude. A priest incants a sutra, marking the needles’ passage from use, and offers a blessing, which is thought to rub off on the person who has made the offering. The essence of hari-kuyo is to honour the needles for their hard work, give thanks for their service over the preceding year, and also to pray for improved needlework skills in the future.

The used needles and pins are often sent to Awashima Shrine, where they are then laid to rest. In some regions, the blocks of tofu and konnyaku, with their pins sticking out, are farewelled by being floated down a river.

Like many older traditions, hari-kuyo has seen a decline in popularity as society has become more modern. As fashions have changed, the kimono has ceased to be an item of everyday wear, and needle use has fallen accordingly. Whereas many years ago needles were an important tool, and needlework was seen as an essential skill that all women had to learn before marrying, needlework is today seen more as a hobby or a craft than a profession, and many women no longer use needles or learn how to sew.

On this particular winter day in 2000, the few dozen women were outnumbered by curious onlookers – both foreign tourists such as myself, and Japanese people who were not familiar with this tradition. As I watched the mainly older women bending over the metal trays of tofu, heads bowed in prayer, I found myself wondering how many more had come to pay their respects in the past, and how few would in future.