Bitcoin Price Fluctuation
Bitcoin prices are constantly changing; prices are determined by demand and supply.
There is a fixed amount/volume of Bitcoins (21 Million) and price goes up if the demand exceeds the volume and vice versa if the demand is low.
The pace of issuance is adjusted by halving the mining fee at a rate of once every four years.
The time when mining reward is reduced to half is called halving and it is one of the causes for price fluctuation.
If you look closely, Bitcoin price may vary from serveral yen to serveral hundred yen depending on exchange. Due to differences in the demand and supply of trading in the exchange, it can be resolved by transactions using Arbitrage transactions.