# United National Heavyweight Championship (Zero1)

The United National Heavyweight Championship (often shortened to UN Championship) was a professional wrestling title in the Japanese promotion Pro Wrestling Zero1. It was one of Zero1's top two singles titles, along with the World Heavyweight Championship. The title was created on January 31, 2004 as the NWA United National Heavyweight Championship. Masato Tanaka, then known as Masa Tanaka, defeated Steve Corino in an Indian strap match to become the first champion. It was created at a time when Zero1 was a member of the National Wrestling Alliance (NWA); when Zero1 departed the NWA in late 2004, NWA ceased recognizing or sanctioning it, though it retained the NWA initials. The title was revived by NWA Pro Wrestling in 2011, with NWA beginning to sanction title matches in Zero1 that same year after Zero1 was reinstated as a member of the NWA. NWA stopped sanctioning the title and the NWA initials were dropped after Zero1 left the NWA again later in 2011. In 2020, the championship was retired. There were a total of 26 recognized champions who had a combined 32 official reigns.

## Title history

Key :
| No. | Overall reign number |
| Reign | Reign number for the specific champion |
| Days | Number of days held |
| Defenses | Number of successful defenses |
| <1 | Reign lasted less than a day |
| + | Current reign is changing daily |
| No. | Champion | Championship change | Championship change | Championship change | Reign statistics | Reign statistics | Reign statistics | Notes | Ref. |
| No. | Champion | Date | Event | Location | Reign | Days | Defenses | Notes | Ref. |
| | (NWA) National Wrestling Alliance / Pro Wrestling Zero1 (Zero1) | (NWA) National Wrestling Alliance / Pro Wrestling Zero1 (Zero1) | (NWA) National Wrestling Alliance / Pro Wrestling Zero1 (Zero1) | (NWA) National Wrestling Alliance / Pro Wrestling Zero1 (Zero1) | (NWA) National Wrestling Alliance / Pro Wrestling Zero1 (Zero1) | (NWA) National Wrestling Alliance / Pro Wrestling Zero1 (Zero1) | (NWA) National Wrestling Alliance / Pro Wrestling Zero1 (Zero1) | (NWA) National Wrestling Alliance / Pro Wrestling Zero1 (Zero1) | (NWA) National Wrestling Alliance / Pro Wrestling Zero1 (Zero1) |
| 1 | Masa Tanaka | January 31, 2004 | U$A – Day 2 | Tokyo, Japan | 1 | 251 | 5 | Defeated Steve Corino in an Indian strap match. | |
| | Pro Wrestling Zero1 (Zero1) | Pro Wrestling Zero1 (Zero1) | Pro Wrestling Zero1 (Zero1) | Pro Wrestling Zero1 (Zero1) | Pro Wrestling Zero1 (Zero1) | Pro Wrestling Zero1 (Zero1) | Pro Wrestling Zero1 (Zero1) | Pro Wrestling Zero1 (Zero1) | Pro Wrestling Zero1 (Zero1) |
| 2 | Takao Omori | October 8, 2004 | New Whirlpool-1 Truth II 2004 – Day 3 | Tokyo, Japan | 1 | 107 | 1 | This was a steel cage match. | |
| — | Vacated | January 23, 2005 | — | — | — | — | — | Vacated due to Omori winning the World Heavyweight Championship of AWA Superstars of Wrestling. | |
| 3 | C. W. Anderson | March 27, 2005 | MAX Strong Wind & Thunder – Day 5 | Tokyo, Japan | 1 | 313 | 0 | Defeated Kohei Sato. | |
| — | Vacated | February 3, 2006 | — | — | — | — | — | Vacated due to a back injury. | |
| 4 | Kohei Sato | February 26, 2006 | Happening – Day 5 | Tokyo, Japan | 1 | 258 | 5 | Defeated Ryouji Sai. | |
| 5 | Ryouji Sai | November 11, 2006 | Max Around '06 – Day 8 | Osaka, Japan | 1 | 117 | 1 | | |
| 6 | Daisuke Sekimoto | March 8, 2007 | Max Satisfaction – Day 1: Ex-Impact | Tokyo, Japan | 1 | 250 | 3 | | |
| 7 | Yoshihito Sasaki | November 13, 2007 | Believe Your Way 2007 – Day 8 – Shinjiro Otani, Takao Omori, Tatsuhito Takaiwa & Kamikaze 15th Anniversary | Tokyo, Japan | 1 | 90 | 1 | | |
| 8 | Sandy Beach | February 11, 2008 | Solidarity – Day 3 | Nagoya, Japan | 1 | 47 | 0 | | |
| 9 | Yoshihito Sasaki | March 29, 2008 | Whirlwind – Day 7 | Sapporo, Japan | 2 | 27 | 0 | | |
| — | Vacated | April 25, 2008 | — | — | — | — | — | Vacated due to injury. | |
| 10 | Kengo Mashimo | May 4, 2008 | Kaientai Dojo's GWSP6 2008 – Day 4: Kengo Mashimo Produce | Chiba, Japan | 1 | 937 | 2 | Defeated Ryouji Sai. | |
| — | Vacated | November 27, 2010 | — | — | — | — | — | Vacated due to inactivity. | |
| | (NWA) National Wrestling Alliance / Pro Wrestling Zero1 (Zero1) | (NWA) National Wrestling Alliance / Pro Wrestling Zero1 (Zero1) | (NWA) National Wrestling Alliance / Pro Wrestling Zero1 (Zero1) | (NWA) National Wrestling Alliance / Pro Wrestling Zero1 (Zero1) | (NWA) National Wrestling Alliance / Pro Wrestling Zero1 (Zero1) | (NWA) National Wrestling Alliance / Pro Wrestling Zero1 (Zero1) | (NWA) National Wrestling Alliance / Pro Wrestling Zero1 (Zero1) | (NWA) National Wrestling Alliance / Pro Wrestling Zero1 (Zero1) | (NWA) National Wrestling Alliance / Pro Wrestling Zero1 (Zero1) |
| 11 | Hartley Jackson | February 19, 2011 | NWA Pro Australia: Meltdown 2011 | Adelaide, Australia | 1 | 263 | 8 | Defeated Robby Heart to become the new NWA United National Heavyweight Champion. | |
| 12 | Shito Ueda | November 9, 2011 | Yarisugi Forever II | Tokyo, Japan | 1 | 13 | 0 | | |
| 13 | Paul Tracy | November 22, 2011 | God's of Shimane Country Tour 2011 – Day 1 | Matsue, Japan | 1 | 2 | 0 | | |
| 14 | Shito Ueda | November 24, 2011 | God's of Shimane Country Tour 2011 – Day 3 | Kumamoto, Japan | 2 | 255 | 4 | | |
| 15 | Yusaku Obata | August 5, 2012 | Midsummer Festival ~ Fire Festival 2012 – Day 11 | Tokyo, Japan | 1 | 72 | 0 | | |
| 16 | James Raideen | October 16, 2012 | World | Tokyo, Japan | 1 | 257 | 1 | | |
| | Pro Wrestling Zero1 (Zero1) | Pro Wrestling Zero1 (Zero1) | Pro Wrestling Zero1 (Zero1) | Pro Wrestling Zero1 (Zero1) | Pro Wrestling Zero1 (Zero1) | Pro Wrestling Zero1 (Zero1) | Pro Wrestling Zero1 (Zero1) | Pro Wrestling Zero1 (Zero1) | Pro Wrestling Zero1 (Zero1) |
| 17 | Ikuto Hidaka | June 30, 2013 | Fusion | Nagoya, Japan | 1 | 30 | 0 | | |
| 18 | Zeus | July 30, 2013 | Fire Festival (2013) – Day 8 | Osaka, Japan | 1 | 170 | 0 | | |
| 19 | Tama Williams | January 16, 2014 | Live event | Tokyo, Japan | 1 | 199 | 2 | | |
| 20 | Hideki Suzuki | August 3, 2014 | Fire Festival (2014) | Tokyo, Japan | 1 | 275 | 2 | | |
| 21 | Kamikaze | May 5, 2015 | Live event | Tokyo, Japan | 1 | 141 | 2 | | |
| 22 | Toshiki Iwaki | September 23, 2015 | Live Event | Tokyo, Japan | 1 | 39 | 0 | Won the match by disqualification; awarded the title by referee Katsumi Sasazaki, who was assaulted by Kamikaze during the match. | |
| 23 | Kamikaze | November 1, 2015 | Live Event | Tokyo, Japan | 2 | 22 | 0 | | |
| 24 | Yoshikazu Yokoyama | November 23, 2015 | Live Event | Tokyo, Japan | 1 | 26 | 0 | | |
| 25 | Masakado | December 19, 2015 | Live Event | Tokyo, Japan | 3 | 190 | 3 | Masakado previously held the title under the name Shito Ueda. | |
| 26 | Buffa | June 26, 2016 | Super Fireworks Captain Super Fireworks | Kakegawa, Japan | 1 | 133 | 1 | | |
| 27 | Hartley Jackson | November 6, 2016 | Kohei Sato 15th Anniversary Show | Tokyo, Japan | 2 | 116 | 0 | This was a three-way match, also involving Kamikaze. | |
| 28 | Sean Guinness | March 2, 2017 | Shinsei Zero1 Dream Series ~ Birthday Party | Tokyo, Japan | 1 | 182 | 0 | | |
| — | Vacated | August 31, 2017 | — | — | — | — | — | Guinness relinquished the title to focus on wrestling as a junior heavyweight. | |
| 29 | Super Tiger | September 30, 2017 | Shinjiro Otani & Tatsuhito Takaiwa 25th Anniversary Convention | Tokyo, Japan | 1 | 190 | 3 | Defeated Hartley Jackson to win the vacant title. | |
| 29 | Chris Vice | April 8, 2018 | 15th Yasukuni Shrine Festival | Tokyo, Japan | 1 | 56 | 1 | | |
| 30 | Shogun Okamoto | June 3, 2018 | Shinsei Zero1 Sapporo First Landing ~ No Gravity Warrior Sugi Sapporo First Visit | Sapporo, Japan | 1 | 280 | 2 | | |
| 31 | Towa Iwasaki | March 10, 2019 | Sayonara West Holy Land Hakata Star Lanes | Fukuoka, Japan | 1 | 314 | 3 | | |
| 32 | Chris Vice | January 18, 2020 | Skill Up To The Future ~ Towards A Dream | Tokyo, Japan | 2 | 106 | 0 | | |
| — | Deactivated | May 3, 2020 | — | — | — | — | — | Vacated due to Vice winning the World Heavyweight Championship; title abandoned. | |

## Combined reigns

As of October 8, 2024.
| † | Indicates the current champion |
| Rank | Wrestler | No. of reigns | Combined defenses | Combined days |
| 1 | Kengo Mashimo | 1 | 2 | 937 |
| 2 | Shito Ueda/Masakado | 3 | 7 | 458 |
| 3 | Hartley Jackson | 2 | 8 | 379 |
| 4 | Towa Iwasaki | 1 | 3 | 314 |
| 5 | C. W. Anderson | 1 | 0 | 313 |
| 6 | Shogun Okamoto | 1 | 2 | 280 |
| 7 | Hideki Suzuki | 1 | 2 | 275 |
| 8 | Kohei Sato | 1 | 5 | 258 |
| 9 | James Raideen | 1 | 1 | 257 |
| 10 | Masato Tanaka | 1 | 5 | 251 |
| 11 | Daisuke Sekimoto | 1 | 3 | 250 |
| 12 | Tama Williams | 1 | 2 | 199 |
| 13 | Super Tiger | 1 | 3 | 190 |
| 14 | Sean Guinness | 1 | 0 | 182 |
| 15 | Zeus | 1 | 0 | 170 |
| 16 | Kamikaze | 2 | 2 | 163 |
| 17 | Buffa | 1 | 1 | 133 |
| 18 | Ryouji Sai | 1 | 1 | 117 |
| 18 | Yoshihito Sasaki | 2 | 1 | 117 |
| 20 | Takao Omori | 1 | 1 | 107 |
| 21 | Chris Vice | 2 | 1 | 106 |
| 22 | Yusaku Obata | 1 | 0 | 72 |
| 23 | Sandy Beach | 1 | 0 | 47 |
| 24 | Toshiki Iwaki | 1 | 0 | 39 |
| 25 | Ikuto Hidaka | 1 | 0 | 30 |
| 26 | Yoshikazu Yokoyama | 1 | 0 | 26 |
| 27 | Paul Tracy | 1 | 0 | 2 |