Japanese firm, Metaplanet, has added ¥1 billion worth of Bitcoin to its holdings, bringing the total to 639.5 BTC.Metaplanet purchased an additional 108.786 BTC, spending approximately AU$91,850 per Bitcoin.The company focuses on Bitcoin as its primary treasury reserve asset to drive global adoption.Metaplanet's share price has tripled since April, reflecting its successful Bitcoin investment strategy.