Once upon a time Lord Matsunaga was riding a dappled gray horse and carrying
a Shigedo Bow, a white feather bow, and white feathered arrows.
When hawking, the god enshrined at the Tosen Shrine, "Kumano-kusumi
no Mikoto" passed the hunting spot. Lord Matsunaga, thinking this
was strange, shot at the Tosen god. When this happened, the god picked
up a small pebble from his "tamoto (sleeve)" and threw it at
Lord Matsunaga. This small pebble through the years has become bigger,
and because it was thrown from the sleeve, is often called either "Tamoto-ishi
(Tamoto Stone)" or "Tsubute-ishi (Thrown Stone)".
The giant boulder exists even today near the Taiko Bridge weighing around 130 tons and standing at a height of 5 m with a circumference of 19 m.
After this, riding a dappled gray horse and carrying a Shigedo Bow has
been prohibited in Arima. It is said that whenever someone violates this
rule when entering Arima, the fair weather becomes cloudy and suddenly
it becomes heavy rain and wind.