The Billboard Japan Hot 100 is a music singles chart in Japan. It has been compiled by Billboard Japan and Hanshin Contents Link ever since February 2008. The chart is updated every Wednesday at billboard-Japan.com (JST) and every Thursday at billboard.com (UTC).
The first number-one song on this chart was "Step and Go" by Arashi on the issue dated March 3, 2008. While most of the songs that have reached number one have been in Japanese, four non-Japanese songs have reached the top position. The first was "Bleeding Love" by Leona Lewis on May 8, 2008, the second one was "Blame It on the Girls" by Mika on September 28, 2009, the third one was "Born This Way" by Lady Gaga on April 11, 2011 and the fourth one was "Glad You Came" by The Wanted on May 20, 2013. On the chart dated March 8, 2010, "Hitomi no Screen" by Hey! Say! JUMP became the chart's 100th number-one. AKB48 has earned the most number-one singles with 29 songs.
From the chart's inception in 2008, to December 2010, the chart combined CD single sales data from SoundScan Japan, tracking sales at physical stores across Japan, and radio airplay figures from Japan's then 32 AM and FM radio stations sourced from the Japanese company Plantech. In December 2010, the chart was expanded to include sales from online stores, as well as sales from iTunes Japan. From December 2013, Billboard added two additional factors to the Billboard Japan Hot 100 chart: tweets relating to songs from Twitter data collected by NTT DATA, as well as data sourced from Gracenote on the number of times a CDs has been registered as being inserted into a computer.
In June 2015, Billboard began publishing the Japan Hot Albums chart, based on a similar methodology to the Billboard Japan Hot 100: combining physical CD sales, digital downloads and Gracenote CD look-ups. Prior to June 2015, Billboard had only published the Japan Top Albums chart: a chart identical to SoundScan Japan's albums chart, except that releases with multiple versions (for example, CD only and CD+DVD editions) had their sales total combined into a single release. The Top Albums chart continues to be published alongside the Hot Albums chart.