:Itoshiki Hibi yo

{{Infobox song

| name = Itoshiki Hibi yo

| cover = Itoshiki Hibi yo cover.jpg

| alt =

| border = yes

| type = single

| artist = Ken Hirai

| album = Japanese Singer

| A-side = Itoshiki Hibi yo

| B-side = Run to You

| released = May 4, 2011

| recorded = 2011

| studio =

| venue =

| genre = Pop

| length = 16:43

| label = Defstar Records

| writer = Ken Hirai, Kiyoshi Matsuo

| producer = Ken Hirai, Reo

| prev_title = Aishiteru

| prev_year = 2010

| next_title = Kokuhaku

| next_year = 2012

| misc = {{External music video|{{YouTube|Ra-9M6ZgT8k|"Itoshiki Hibi yo"|link=no}}}}

}}

{{nihongo|"Itoshiki Hibi yo"|いとしき日々よ||lit. "Oh Sweet Days"}} is the thirty-fourth single by Japanese recording artist Ken Hirai.{{cite news|url=http://news.music.biglobe.ne.jp/201104/article_45.html |title=平井堅 「JIN-仁-」で約3年ぶりとなるドラマ主題歌の発売が決定 |publisher=Biglobe Music. Biglobe |accessdate=2011-06-12 |date=2011-04-18 |language=Japanese}} The song was written by Hirai, composed by Kiyoshi Matsuo and production was handled by Hirai. It was released on May 4, 2011 as the fifth single from Hirai's eighth studio album Japanese Singer.{{cite news|url=http://natalie.mu/music/news/49126 |script-title=ja:生まれてこのかた純国産、平井堅3年ぶりアルバム完成 |publisher=Natalie |accessdate=2011-06-12 |date=2011-05-10 |language=Japanese}} "Itoshiki Hibi yo" serves as theme song for the second season of the TBS drama Jin. The B-side, "Run to You" is used in Nexco Central Japan commercials starring actress Aya Ueto.

The single debuted at number 9 on the Oricon Daily Singles Chart on May 3, 2011 and climbed to number 4 on May 9, 2011.{{cite web |url=http://blog.oricon.co.jp/earo/archive/4882/0 |title=韓国の男性5人組・MBLAQの1stが首位浮上／前日首位・ぱすぽ4位に☆5/3付 シングルデイリー |work=Oricon |accessdate=2011-06-12 |date=2011-05-04 |language=Japanese |archive-url=https://web.archive.org/web/20110929225740/http://blog.oricon.co.jp/earo/archive/4882/0 |archive-date=2011-09-29 |url-status=dead }}{{cite web |url=http://blog.oricon.co.jp/earo/archive/4897/0 |script-title=ja:チャン・グンソク首位返り咲き／ぱすぽ☆50位圏外へ☆5/9付 シングルデイリー |work=Oricon |accessdate=2011-06-12 |date=2011-05-10 |language=Japanese |archive-url=https://web.archive.org/web/20110929225818/http://blog.oricon.co.jp/earo/archive/4897/0 |archive-date=2011-09-29 |url-status=dead }} It peaked at number 7 on the Oricon Weekly Singles Chart with 13,766 copies sold.{{cite web|url=http://www.oricon.co.jp/search/result.php?kbn=js&types=rnk&year=2011&month=5&week=3&submit5.x=34&submit5.y=6 |script-title=ja:2011年05月第3週の邦楽シングルランキング情報 |publisher=Oricon |accessdate=2011-06-12 |language=Japanese}} The single ranked at number 24 on the Oricon Monthly Singles Chart for the month of May 2011 with 22,456 copies sold.{{cite web |url=http://blog.oricon.co.jp/gekkan/archive/2/0 |script-title=ja:シングル月間ランキング 2011年05月度 |work=Oricon |accessdate=2011-06-12 |date=2011-06-12 |language=Japanese |archive-url=https://web.archive.org/web/20120322213943/http://blog.oricon.co.jp/gekkan/archive/2/0 |archive-date=2012-03-22 |url-status=dead }}

The song was certified platinum for digital downloads by the RIAJ.{{cite web|script-title=ja:レコード協会調べ 1月度有料音楽配信認定 |trans-title=Record Association Investigation: January Digital Music Download Certifications |url=http://www.riaj.or.jp/data/others/chart/w140228.html |publisher=Recording Industry Association of Japan |language=Japanese |date=February 28, 2014 |accessdate=March 4, 2014 |url-status=dead |archiveurl=https://web.archive.org/web/20140305015635/http://www.riaj.or.jp/data/others/chart/w140228.html |archivedate=March 5, 2014 }}

"Itoshiki Hibi yo" was voted third most popular drama theme song of the spring season in a RecoChoku user poll.{{cite web|url=http://www.barks.jp/news/?id=1000069875 |title=春ドラマ主題歌人気ランキング、1位はSMAP「not alone～幸せになろうよ～」 |publisher=Barks |accessdate=2011-06-12 |date=2011-05-13 |language=Japanese}}