The festivities are steeped in centuries-old traditions and are always attended by dignitaries from more than 180 countries.
This year, around 2000 guests attended yesterday's banquet, with Crown Princess Mary - from Tasmania - and Crown Prince Frederik, looking regal as ever.
Prince Frederik looked suave in a sleek navy suit, while Princess Mary wore a white cocktail dress with sheer sleeve detail, and wearing her hair in a loose, low bun.
Other royals in attendance were Queen Maxima of the Netherlands and her husband, King Willem-Alexander.
While the Prince of Wales was in attendance for the exciting new era of Japanese royalty, his wife Camilla Parker Bowles opted not to travel with her husband for one very interesting reason.
Last year, the 71-year-old admitted for the first time that she had a deep fear of flying when the Royal appeared on ITV's This Morning.
Her phobia has meant the Duchess often will miss royal engagements with Prince Charles and has led to her cutting her overseas trips short in the past, including the couple's visit to Australia in April 2018.
From England, flights to Japan can take up to 20 hours, so it is understandable that Camilla has decided to let Charles fly solo.
However, instead of going to Japan, one of the hardest-working royals has a number of engagements lined up to keep herself busy while Charles is away.
This week, the Duchess of Cornwall will open the new Royal National Hospital for Rheumatic Diseases and Brownsword Therapies Centre at the Royal United Hospitals Bath (RUH) on Tuesday.
Later in the week, Camilla will attend a tea reception in London.