Senjutsu (Japanese: 戦術, "Tactics") is the seventeenth studio album by English heavy metal band Iron Maiden, released on 3 September 2021. Their first album in six years, it was a critical and commercial success, praised for its ambitious epic scope. Two singles, "The Writing on the Wall" and "Stratego", were released to promote the album.

Senjutsu is the band's first studio album in nearly six years (although having been put on hold for well over two years), following 2015's The Book of Souls, marking the longest gap between two Iron Maiden studio albums. This is also their second studio double album, and their first studio album since 1984's Powerslave to have no songwriting contributions from guitarist Dave Murray in any way, as well as the first since 1998's Virtual XI to feature multiple songs written by bassist Steve Harris alone.

The name of the album is rendered on the right side of the cover art by the actual vertical Japanese spelling of "senjutsu" (戦術), and on the left side by a font reminiscent of Japanese characters.

Released on 3 September 2021, it received a positive response from most fans and music critics, eventually reaching the top of the bestseller lists of 27 countries, including Belgium (Wallonia and Flanders), Chile, Brazil, Bolivia, Colombia, Mexico, Bulgaria, Romania, Greece, Austria, Switzerland, Germany, Hungary, Croatia, Malaysia, Serbia, Indonesia, Russia, South Africa, Finland, Italy, Portugal, Spain, Sweden, Thailand, India and South Korea.

In the comparison of sales of physical albums in the UK, the double-disc release took the first position, also noted on the European Album Chart Top 200. The album was ranked second on the world music charts. 17th studio effort also gave the band its highest chart position in the US debuting at number three on Billboard Top 200 Albums Chart and number one on Billboard's Physical Albums Chart. Senjutsu was also in the Top 3 bestsellers in the USA (the highest in the group's history so far), Australia, Ireland, Great Britain (first on the lists in Wales and Scotland), Singapore, Israel, UAE, Japan, the Netherlands, France, Czech Republic, Slovakia, Montenegro, Poland, Estonia, Costa Rica, El Salvador, Nepal, Honduras, Uruguay, Cyprus, Latvia, Bosnia and Herzegovina, Luxembourg, Taiwan, Malta and Ukraine.

In South America and Africa, the album went on sale only one week after the official release date. In total, the group's seventeenth album reached the top three bestsellers in 55 countries around the world and the Top 5 bestsellers in 63 countries. Senjutsu turned out to be a tremendous achievement, strengthening the group's brand on the global music market.

Senjutsu marks the second use of the band's original logotype (with the extended letters R, M and N) on a studio album cover since 1995's The X Factor, the previous one being for 2015's The Book of Souls. The album cover by Mark Wilkinson presents Eddie dressed up as a samurai and holding a katana. Harris sent Wilkinson reference material of Oni creatures and kabuki paintings and masks, and the artist spent a day seeing the Japanese exhibits on the Victoria and Albert Museum for further inspiration. His first draft had a close-up on Eddie's face like Wilkinson's work in the previous album The Book of Souls, before he sent another with Eddie wearing a helmet - without the visor to not hide his face - holding a sword, which Harris decided to use as the cover while keeping the other in the back. Mark Wilkinson told UK's Metal Hammer magazine: "I knew I would have difficulty just plonking Eddie into samurai costume. The higher caste warriors usually had many layers of highly ornate, dense fabric both to project and pad them out on the battlefield – I couldn't see such a costume working for the skeletal figure of Eddie. Besides, he would look far too flamboyant. I also resisted putting the traditional samurai helmet on his head. It would cover too much detail of the early kabuki-style 'mask' of red warpaint I had sketched out for him. The helmet 'cowl' and 'fukigaeshi' earpieces were like skin and bone attachments. Eddie's head was like a cyborg – part creature, part machine – especially with all the bashed in metal and torn rustic leather of the rest of his costume". The gatefold featured an artwork which Harris commissioned to inspire the band's stage set, featuring Eddie standing in front of a Pagoda surrounded by dead warriors, in a landscape that Wilkinson drew based on the Shotley Peninsula.

At Metacritic, which assigns a normalised rating out of 100 to reviews from professional publications, the album has an average score of 83 based on 15 reviews, indicating "universal acclaim". At AnyDecentMusic?, which collates reviews from more than 50 media sources, the album scored 7.9 out of 10, based on 17 reviews. AllMusic awarded it 4 out of five, stating, "Clocking in at just over 80 minutes, the epic Senjutsu is another distended late-career triumph, albeit one that requires multiple spins to set up camp in your Homeric metal-craving cranium". Wall of Sound scored the album 9/10, calling it an "(...) epic and triumphant return for the lads... better balanced [than The Book of Souls]... with some interesting songwriting". The Guardian awarded it with the highest note and praising Senjutsu as "(...) an ambitious, eccentric master piece". Classic Rock's journalist Dave Ling awarded Senjutsu with 4.5 stars out of 5 describing band's effort as "(…) a remarkable album from a band that still has plenty to say and to offer".