Here are April's official Shooto rankings, as released by the International Shooto Commission.
I didn't include anything above welterweight, as the heavier divisions are mostly inactive of late.
Photos by Shooto, GBRing, Dan Herbertson for Sherdog,

Flyweight (-52kg / 115 lbs.)

Champion: Rambaa "M-16" Somdet (7-2 / Thailand / M-16 Muay Thai)

1. Noboru "Shinpei" Tahara (8-4-1 / Japan / Hajimail STF)
2. Junji "Sarumaru" Ito (6-2 / Japan / Shooting Gym Yokohama)
3. Hiroyuki Abe (6-2 / Japan / K'z Factory)
4. Atsushi "ATCH Anarchy" Takeuchi (7-5-2 / Japan / Paraestra Tokyo)
5. Katsuya Murofushi (5-4 / Japan / roots)
6. ↑ "Heat" Takeshi Sato (8-9-1 / Japan / Wajyutsu Keisyukai RJW)
7. ↓ Junji Ikoma (12-12-4 / Japan / Chokushinkai)
8. Shinya Murofushi (5-2-1 / Japan / Submit Shizuoka)
9. Takehiro Harusaki (5-5-1 / Japan / Chokushinkai)
10. ↑ Jesse Taitano (7-7-2 / USA / Spike 22)

- Still no date for Rambaa Somdet's first title defense.
- Junji Ikoma (#7) slides down one spot after a third round TKO loss to "Shinpei" Tahara (#1) on March 28th.
- Guam's "Spiderman," Jesse Taitano, will drop to flyweight for his next bout and enters the rankings at #10.

Bantamweight (-56kg / 123 lbs.)

Champion: vacant

1. Yasuhiro Urushitani (16-4-6 / Japan / Wajyutsu Keisyukai RJW)
2. Ryuichi Miki (10-3-3 / Japan / Gutsman Shooto Dojo)
3. Mamoru Yamaguchi (23-5-3 / Japan / Shooting Gym Yokohama)
4. Jussier "Formiga" da Silva (3-0 / Brazil / Nova Uniao)
5. ↑ Yuki Shojo (10-5-2 / Japan / X-One Gym Shonan)
6. ↓ Shinichi "BJ" Kojima (10-4-5 / Japan / Reversal Gym Yokohama)
7. Fumihiro Kitahara (7-1-1 / Japan / Paraestra Sapporo)
8. Ayumu "GoZo" Shioda (7-7 / Japan / Paraestra Hachioji)
9. Masaaki Sugawara (9-4-1 / Japan / Wajyutsu Keisyukai Duro)
10. Takuya Mori (6-4-1 / Japan / Paraestra Sapporo)

- The well-acquainted Yasuhiro Urushitani (#1) and Ryuichi Miki (#2) will square off for a third time on May 30th, this time with the vacant world title on the line. Urushitani took a unanimous decision in their last meeting, which was preceded by a draw.
- Yuki Shojo (#5) moves up a spot with his March 22nd decision win over Jesse Taitano.
- Inactive former champ "BJ" Kojima (#6) continues to slide down the rankings after relinquishing his title in February due to a knee injury. He's expected to return by the end of the year.

Featherweight (-60kg / 132 lbs.)

Champion: ↑ Shuichiro Katsumura (11-7-3 / Japan / Reversal Gym Yokohama)

1. ↑ Koetsu Okazaki (6-1-1 / Japan / freelance)
2. ↑ Eduardo "Dudu" Dantas (8-2 / Brazil / Nova Uniao)
3. ↓ Masakatsu Ueda (10-1-2 / Japan / Paraestra Tokyo)
4. Hiromasa Ogikubo (6-1-2 / Japan / Paraestra Matsudo)
5. Tetsu "Hadairo" Suzuki (10-7-3 / Japan / Wajyutsu Keisyukai Nakedman)
6. ↑ So Tazawa (8-5-4 / Japan / Gutsman Shooto Dojo)
7. ↑ Luiz Alberto "Betao" Nogueira (8-1 / Brazil / Renovacao Fight Team)
8. ↑ Teriyuki Matsumoto (6-3 / Japan / Shooting Gym Osaka)
9. Akitoshi Tamura (14-8-2 / Japan / Tsudanuma Dojo)
10. ↓ Marcos "Louro" Galvao (6-3-1 / Brazil / Nova Uniao)

- Shuichiro Katsumura shook up the 132-pound division last month when he choked out formerly undefeated champ Masakatsu Ueda (#3) at "The Way of Shooto 2" (video). The heavy underdog was previously ranked sixth.
- "Dudu" Dantas (#2) will return to Japan to face Hiromasa Ogikubo (#4) at Sustain's big JCB Hall show on May 30th.
- Former lightweight Akitoshi Tamura enters the featherweight rankings in the #9 slot.
- Marcos Galvao drops from #1 to #10 after not competing in Shooto for 18+ months.

Lightweight (-65kg / 143 lbs.)

Champion: "Lion" Takeshi Inoue (18-3 / Japan / Shooting Gym Yokohama)

1. Hatsu Hioki (20-4-2 / Japan / Alive)
2. Renan Barao (20-1 / Brazil / Nova Uniao)
3. Taiki Tsuchiya (6-2 / Japan / roots)
4. Hideki Kadowaki (13-10-2 / Japan / Wajyutsu Keisyukai Tokyo)
5. Issei Tamura (5-0 / Japan / Krazy Bee)
6. Gustavo Falciroli (9-2-2 / Australia / Mach 1)
7. Hiroshi "Iron" Nakamura (9-4-5 / Japan / Tokyo Yellow Mans)
8. Matteus Lahdesmaki (8-4-3 / Finland / Shooto Lahti)
9. "Wicky" Akiyo Nishiura (10-5-1 / Japan / STGY)
10. Paulo "Guerreiro" Dantas (19-5 / Brazil / Sport Fight)

- "Son of Shooto" Hatsu Hioki (#2) returns to challenge for "Lion" Takeshi's title on May 30th.
- Hideki Kadowaki (#4) will meet Gustavo Falciroli (#6) at the Shooto-affiliated Superfight Australia on June 11th.
- Brazilian standout Paulo Dantas enters the rankings at #10.

Welterweight (-70kg / 154 lbs.)

Champion: Willamy "Chiquerim" Freire (15-2 / Brazil / Nocaute Fight)

1. Yusuke Endo (13-3-2 / Japan / Gokita Gym)
2. Takashi Nakakura (11-3-1 / Japan / Shooting Gym Osaka)
3. Takanori Gomi (31-6, 1 NC / Japan / Rascal Gym)
4. Bendy Casimir (19-6-2 / France / Haute Tension)
5. ↑ Paulo "Bananada" Goncalves (13-7 / Brazil / Tata Fight Team)
6. ↓ Kenichiro Togashi (10-7-5 / Japan / Paraestra Hiroshima)
7. ↓ Mizuto Hirota (12-4-1 / Japan / freelance)
8. ↓ Kotetsu Boku (16-6-2 / Japan / Krazy Bee)
9. ↓ Ganjo Tentsuku (9-4-2 / Japan / Purebred Omiya)
10. Yoshihiro Koyama (14-3-1 / Japan / Paraestra Matsudo)

- Willamy "Chiquerim" will make his first title defense against Pacific Rim champion Yusuke Endo (#1) on May 30th. The Brazilian submitted Endo with a guillotine in May of last year (video).
- Ganjo Tentsuku (#9) faces Daisuke Nakamura at Hidehiko Yoshida's "Astra" retirement show this Sunday.
- Paulo "Bananada" (#5) enters the rankings after besting Nova Uniao's Giovani Diniz at Shooto Brazil 15 in March.