Very late this month... sorry.
At least it is a rather quiet month for Japanese releases, with only one major regular release item (Bruticus)

These are TakaraTomy toys (and maybe some significant licensed items) currently known from official sources, scheduled for release in JUNE in Japan (as well as in Asia as most Japanese Transformers toys are also released through Hasbro Hong Kong).

These monthly lists are archived on the Transformers Checklist here if you need to refer to these listings later (if anything is found out later, these monthly lists won't be updated after their month ends).
Some recent listings for reference...
May 2016 list
April 2016 list
March 2016 list
February 2016 list
January 2016 list

Dates and details can change at any time - Approximate yen prices listed are just a rough guide to their retail price in Japan.
Links were active at the time they were first added and are only there for reference/proof of details - I do NOT endorse or promote any of those businesses.
(posting corrections or additions are greatly appreciated)

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JUNE

Masterpiece
- MP-25L - Loudpedal (black redeco Tracks w/ Raoul? & Microman Blaster) - June 11-12 (Tokyo Toy Show excl) - 8,500yen.

Unite Warriors
- UW-07 - Bruticus - Onslaught, Blast Off (new mould), Brawl, Swindle, Vortex (modified mould) - June 25th (15,000yen)

Legends EX
- Rhinox (minor redeco 2014 Voyager Generations) - TakaraTomyMall exclusive - June 28th (first sold at Transformers Festival - May 7th) 5600yen
- Rattrap (minor redeco 2014 Deluxe Legends) - TakaraTomyMall exclusive - June 28th (first sold at Transformers Festival - May 7th) 3780yen
- Waspinator (minor redeco Deluxe 2014 Generations) - TakaraTomyMall exclusive - June 28th (first sold at Transformers Festival - May 7th) 3780yen

Adventure
- TAV50 - Hyper Surge Optimus Prime (new with armour parts) - June 25 (8,000yen)

TakaraTomy ARTS Capsule
- Q-Transformers figurines - (Movie Optimus Prime, Movie Bumblebee, Movie Lockdown, Gen1 Jazz, Gen1 Arcee) - June 30 (300yen each)
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CONFIRMED FUTURE ITEMS
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JULY

Legends
- LG-21 - Hardhead (Titans Return Deluxe w/ Titanmaster Terri-Bull's vehicle) - July 23 (4000yen)
- LG-22 - Skullcruncher (Titans Return Deluxe w/ Titanmaster Crashbash's vehicle) - July 23 (4000yen)
- LG-23 - Galvatron (Titans Return Voyager) - July 23 (5000yen)

Adventure
- TAV51 - Hypersurge Bumblebee with Minicon (minor redeco of Hasbro version) - July 23rd (4,500yen)
- TAV52 - (Battlepack) Torrent Armor Strongarm with Sawtooth (minor redeco of Hasbro version) - July 23rd (2500yen)

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AUGUST

Masterpiece
- MP-31 - Delta Magnus (redeco Ultra Magnus) - August 27th (18,000yen)

Unite Warriors
- UW-08 - Computron - Scattershot (minor redeco w/ new heads), Strafe (new mould), Lightspeed (redeco Wheeljack w/ new head), Afterburner (remould groove), Nosecone (remould rook) - August 27th (15,000yen)

Legends
- LG-24 - Shockwave & Cancer (Generations Legends with Titanmaster) - August 27th (1800yen)
- LG-25 - Blurr (Titans Return Deluxe) - August 27th (3100yen)
- LG-26 - Scourge (Titans Return Deluxe) - August 27th (3100yen)

Adventure
- TAV53 - Hypersurge Sideswipe with Minicon (minor redeco of Hasbro version) - August (date TBC) (5,000yen)
- TAV54 - "Scorponok" (likely minor redeco of Hasbro Warrior) - August (date TBC) (2500yen)

Kabaya DX Model kits (licensed - not by TakaraTomy)
- Fortress Maximus Metallic Version w/ Powerglide, Windcharger & Cerebros (minor redeco - possibly shinier plastic) - August (date TBC) (4,000yen for a box of 6 packs, which equals 2 full Fort Max models)

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SEPTEMBER

Masterpiece
- MP-14+ - (Red) Alert Anime Color Edition (minor redeco) TakaraTomyMall exclusive - September 24th (8,400yen)
- MP-27 - Ironhide (reissue with bonus drill) Hasbro Hong Kong exclusive - late September

Legends
- LG-27 - Broadcast (Blaster) (Titans Return Leader) - September 24th (8000yen)
- LG-28 - Rewind & Nightbeat (Generations Legends with Titanmaster) - September 24th (1900yen)
- LG-29 - Wheelie & Go Shooter (Generations Legends with Titanmaster) - September 24th (1900yen)
- LG-30 - Weirdwolf (Titans Return Deluxe with Titanmaster Apeface's vehicle) - September 24th (4000yen)
- LG-31 - Fortress Maximus (Titans Return Titan) - September 24th (25,000yen)

Adventure
- TAV55 -Windblade (likely minor redceo of Hasbro Warrior) - September (date TBC) (2500yen)
- TAV56 - Optimus Prime "Power Surge mode" (likely minor redeco of Hasbro Warrior) - September (date TBC) (2500yen)

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OCTOBER

Masterpiece
- MP-32 - Beast Convoy (Optimus Primal) - October 29th (11,000yen)
- MP-11NT - Thrust (remould Ramjet) - TakaraTomyMall exclusive - October (day TBA) (15,984yen)

Unite Warriors
- UW-EX - Lynx Master (Sky Lynx, Hound, Wheeljack, Ratchet, Trailbreaker - minor redecos) TakaraTomyMall exclusive - October (day TBA) (16,200yen)

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UNKNOWN DATE (at time of posting)

Masterpiece
- MP-?? - Inferno - (date TBC)
- MP-?? - Cheetus (Cheetor) - (date TBC)

Legends
- LG-?? - Super Ginrai (remould TR Leader Powermaster Optimus) - (date TBC)


CANCELLED?

Adventure Verses 2-packs
- TAV VS06 - Strong Arm Battle Mode (redeco Strongarm), & Sideswipe Battle Mode (redeco Sideswipe) & Fixit (Legends Fixit) CANCELLED? (was November 30th 2015 then February 5th 2016) (5500yen)

Q-Transformers
- QTF10 - Grimlock (redeco Movie Bumblebee with new head) - CANCELLED? (was April 2016)
- QTFS03 - Decepticon Jets Set (re-release? of Starscream, Thundercracker, Skywarp) - CANCELLED? (was April 2016)

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