Ys IV: Mask of the Sun (SFC) Review

Received: September 10th, 2012 / Written: April 3rd-9th, 2017

 

Year: 1993 | Developed and Published by: Tonkin House

Licensed by: Nihon Falcom | [ ⬤ ]

Disclaimer: Might contain spoilers... to other games
Hello everyone, StarBoy91 here, passionate about video games, big retrophile, and fan of all things 16-bit.  =)

Seeing Adol off on a brand new adventure

Nihon Falcom's Ancient Ys Vanished A-RPG diptych series took Japan by storm when they debuted in 1987 and 1988 respectively, even more so when the two games were joined together in the PC Engine CD/TurboGrafx CD compilation Ys I + II/Ys Book I & II and stayed together since in subsequent versions (among those the Nintendo DS and PlayStation Portable), thanks to the simple yet intuitive controls, great rock soundtrack, and a gradually developing and highly detailed narrative; however when their third game Ys III: Wanderers from Ys arrived in 1989 it was met with a mixed reaction by many who played it on account that it deviated from its intended bird's eye perspective by making it a sidescrolling A-RPG a la Zelda II: The Adventure of Link (many felt this was the wrong approach) and lacked the longevity and area depth of its predecessors.

It would be another four years until another Ys game followed suit (by this point former Nihon Falcom key members Tomoyoshi Miyazaki and Masaya Hashimoto would leave to form up the tragically short-lived developing company Quintet after working on the first three Ys titles), but due to Nihon Falcom's commitment to other video game projects at the time they could not directly work on it themselves, so they tasked Tonkin House (who ported Ys III to the Nintendo 16-bit console, the only title out of the Ys games on the system to also see an American release courtesy of American Sammy) to craft the fourth title with the material given to them by Nihon Falcom, which would take place after the second game but before the events of the third game.  Enter Ys IV: Mask of the Sun, debuting on the Super Famicom on November 19th, 1993, being the first iteration of the series to not have originally been made available on a computer firsthand, being an SFC console exclusive at the time.  Never having left Japan (officially, at least) it also used to be the canon fourth entry in the series, but more on that later.  Did Tonkin House hit a home run with today's game?

The story once again centers around the teenaged crimson-haired hero Adol Christin who became a renowned hero following his previous overarching adventure he embarked on in Esteria that culminated in finding and restoring the land of Ys back to its former glory after having "vanished" above the clouds seven hundred years prior.

One day as he stands at a beach in Minea he thinks back to the pivotal moments of his adventure where he took down Dark Fact first until finally in the end he vanquished the evil Darm, who was the reason it didn't remain on the ground.

Once Adol destroyed the black pearl Darm clung onto the land of Ys returned back to its original position destroying the monsters in the process and is congratulated by the descendants of the six Priests of Ys and the Goddesses Lair and Feena, the latter of whom would go back to a magic sleep to ensure that Esteria is protected and that the Black Pearl's magic cannot start again--during this point he's maintained the promise he made to Feena to remember her for the normal girl she was in her first encounter with him before she regained her memories.

Once he's done thinking back to that moment something shiny catches his eye on the shore, which turns out to be a bottle.

Upon picking it up he notices a letter inside, but it's written in a language he does not understand; he brings it to Luta Gemma's attention and manages to translate it for Adol.

The message was made from an unknown person specifically to reach Adol beckoning him to come to the land of Celceta and save it from a mysterious evil.  Always yearning for a new adventure in the hopes to be an inspiration to others he accepts the offer and departs from Minea right away to take this opportunity.

Now exploring a new land, what dangers will await Adol Christin this time?

Now the adventure truly starts

Like the Ancient Ys Vanished diptych before it Ys IV: Mask of the Sun is viewed from a top-down perspective where Adol Christin can only move in four directions and mainly takes down enemies by simply shoving them or pushing them with his sword--you must do this adjacent of the enemy at either their left or right sides, but if you take them head on from their center you'll risk sustaining damage yourself and won't be able to cause as much damage to them in the process.  With each enemy or boss that's defeated you'll be netting experience points which vary depending what level you're at as well as set amounts gold value, and once you get an exact amount of experience points you'll level up thereby upgrading your stats and augmenting your health and magic capacity where the process starts anew until you reach the level cap.

Don't worry about her Adol, she can take care
of herself

Pressing Start will pause the game, but by pressing Select you'll be accessing your menu where you can access your equipment and item screens, see your current overall stats (which can also be viewed when holding down either shoulder button at any point of the game), save and load your progress in and from any one of five files (ten less than the Nintendo 16-bit port of Ys III), and customize the options if you so choose to desire (namely for dialogue speed setting, button functions, and an optional screen saver that can be enabled if you set it for at least one minute or so without activity--personally I choose not to use that).

Exploring the wooden infrastructure

The default controls are A to accept and choose something, B to cancel, and Y to use an item that you've currently equipped when the moment calls for it.  There aren't any magic rings in this game like there were in the previous Ys installments but like the second and third games you will require MP when it comes to conjuring magic, which in this game is done by pressing the X button if you've equipped a magically enhanced sword which will either shoot fire projectiles or replenish your health to name a couple examples.  When standing still in the overworld outside or at a safe haven Adol will gradually replenish his health which will stop momentarily should you move until you hold still again.  Except during boss battles you can save at any point of the game (I sincerely recommend that you save often) plus after a boss has been defeated your entire current health and magic capacity will be fully replenished.

Treehouse village

Visually it's simplistic to look at but nevertheless its worlds have got a good sense of distinctive detail to them, and I love how like in the preceding games in the series it's all viewed on a golden leaf frame.  =)  Some of the examples I really like are the treehouse villages with all the trees and foliage in the backdrop (and how you can even walk behind the foreground trees as a way to add visual depth), the water effects are decently nice when it comes to the port sections, there are some nice backdrops of the mountains on a few occasions (especially as you ascend the penultimate tower section until it gets to the point where it's mostly sky), and there's this one forest area where it starts off bright but not long after you get into it begins to get darker as it begins to rain swiftly at a diagonal angle (the first time you enter it there's also thunderstorms).

Fighting close to a muddy sinkhole

One of my favorite areas in the game transpires in an icy cavern, for many reasons: the color scheme is appropriately cool with occasional ice sparkling here and there, but another reason for it is the reflective surface of the icy floor that captures the reflection not just of the statues or doors but also the monsters and Adol which makes me happy as it takes me back to when it happened during the very first Ys game.  =)  There's this water-induced path that leads to the volcano which has a nifty bouncing water effect below you as well as the color-layering waterfalls in the foreground which I like, the lava rooms are glowing red, and the villages are pleasant to look at.  The intro and final shot have an excellent anime quality to them, and the background for when you face the final boss is pretty cool in terms of how it shifts and bends.

First boss fight

The sprites for Adol, the good and bad NPCs, and the normal-sized enemies are small but well-designed and exhibit little animation (Adol gets away with it for moving swiftly); my only quibble is that Adol's right sprites are exactly like his left sprites, which wouldn't be an issue if he wasn't carrying a shield with his left hand and his sword with his right hand (magically switching hands when facing the right; Tonkin House did the same for their port of Ys III).  If it's to make the character subtly ambidextrous I might give it a pass but other than that it's a very minor distraction for me; games on the Nintendo 16-bit console like Lagoon, SoulBlader/SoulBlazer, and Chō Makai Taisen! Dorabotchan/The Twisted Tales of Spike McFang proved that you can get past this facile spriteflipping trap that many a game fell for in the early '90s.  Among the enemies you fight are blobs, grinning sentient trees, projectile spewing Venus fly traps, giant flies, Medusa creatures (or equivalents, rather), sorcerers, et al; meanwhile many of the big bosses are huge and animate decently (some of them, like the ice cavern boss, have got neat entrances).

Meeting Leeza, the messenger of the bottle

Once again the soundtrack is engagingly rock-flavored, this time provided by six of Cube Corporation's composers/sound providers (or "sound manipulators" as they're credited as): Yoshiaki Kubotera (Blue Almanac/Star Odyssey, Human Sports Festival, 46 Okunen Monogatari: Harukanaru Eden e/E.V.O.: Search for Eden), Masanori Hikichi (Human Sports Festival, Advanced Busterhawk Gleylancer, 46 Okunen Monogatari), Miyoko Kobayashi (PC Engine CD Langrisser), Naoyuki Iwai, Tomohiro Endō (46 Okunen Monogatari), and Masumi Takamoto (Dragon Quest IV/Dragon Warrior IV, Tetris 2 + BomBliss).  The music does a very good job at lending it a sense of atmosphere while at the same time being catchy and up tempo for the most part, with the quieter moments being appropriately slower paced.  The awesome thing is that Hikichi and Kobayashi would go on to compose the music for Quintet's Nintendo 16-bit swansong Tenchi Sōzō/Terranigma, one of the best scores (and by extension one of the best games) on the console--that's right, two composers who worked on Ys became the whole composing team of that classic, brilliant!  =D

It's raining hard

The introduction theme sets the tone for the adventure Adol is about to start which is good but at times sounds rather somber, the theme that plays when Adol is boarding the boat to Celceta is adventurously upbeat, and one of the village themes is pleasant-sounding.  The electric guitar during the first battlefield, ice cavern, and penultimate tower themes is very effective and the melodies work as well; I also like this game's take on Adol Christin's theme (albeit on a different pitch) during the citadel portion.  The themes for the wooden infrastructures and the raining forest area are atmospheric in their own right, the regular boss theme is hectic, and the final boss theme has got a supercharged composition.

YES, reflective icy surfaces  =D

Among some of the slower melodies the treehouse village theme is relaxing to listen to, Leeza's theme when you first meet her is sad-sounding, one of the themes is spiritual, when exploring Minea after reentering it (after the threat is vanquished) its theme is atmospherically slow-paced, and when entering Lance Village there is a beautifully soft-sounding remix of its theme from the second Ys which I felt was very welcome as this game feels closely tied to the first two iterations.  =)  The sound effects are decently selected; with Adol's enemy shoving sounding like scratches, the sound for when you procure important items sounding a lot like the item sound cue from Metroid, the bumping sound for when Adol gets damaged by an enemy or boss, and the way the bosses sound as they disappear into a dissolve after vanquishing them.

Exploring inside a pyramid

As was the case in the two earlier Ys games each enemy has a set experience point value attributed to them which decreases the stronger you get as you level up (but their gold value will always remain constant), and what I do is fight them over and over until I level up to the point where they're worth one experience point in which case I move on to the next segment.  Luckily Adol is so nimble and quick on his feet that backtracking and level grinding isn't an issue, and it's here that you can take advantage of enemy respawning after scrolling the screen a bit to a certain side and then returning to the opposite side you emerged from.

Oh, that elegant foliage backdrop

Ys IV: Mask of the Sun was only released in Japan and to this day hasn't seen the light of day in the West, but in the past several years there have been unofficial fan-made translations for it on emulators for emulator users for which its ROM plus translation patch got converted to NTSC and PAL SNES repro carts (this despite the Nintendo 16-bit port of Ys III never seeing a PAL conversion at the time).  In 2005 Taito released the Arc System Works remake titled Ys IV: Mask of the Sun - A New Theory on the PlayStation 2, but exclusively in Japan.  Today's game used to be the official fourth canon entry in the series, but it wasn't the only game in the series at the time under the "Ys IV" moniker.

Image from Wikipedia

Just like Nihon Falcom tasked Tonkin House to create the Super Famicom game with their material, so too did they task Hudson Soft (who ported all three games to the NEC PC Engine CD/TurboGrafx CD) to create their take on the fourth game to the PC Engine Super CD-ROM² console with material given to them by the license owners Nihon Falcom in the form of Ys IV: The Dawn of Ys that December of 1993.  Not owning a PC Engine of any sort I never played it myself but I hear many good things about it, and despite it sharing the same plot as the Super Famicom game Hudson Soft apparently took a lot of liberties with the license; I remember some people calling it the highlight of the Ys series, in spite of its non-canon status.  A third version was planned of Ys IV to be made on Sega's MegaDrive console but sadly got cancelled halfway in development.

Image from Wikipedia

On September 2012 the PlayStation Vita handheld system saw the release of Ys: Foliage Ocean of Celceta which was developed by Nihon Falcom themselves, seeing an official American and European release as Ys: Memories of Celceta in 2013 and 2014 respectively--due to Nihon Falcom's direct involvement it effectively replaced Ys IV: Mask of the Sun as the official fourth game in this growing series.  A part of me is curious, but it's not enough for me to invest in a PlayStation Vita (I'm not going to buy a system to play only one game, it would be a waste in my eyes).

Quaint and lively village, this is

I remember finding out about this game several years ago when I saw some gameplay videos of it on YouTube, and how my desire to play it grew after enjoying my first foray of the series when I downloaded Ys Book I & II on the Nintendo Wii Virtual Console in 2008 and subsequently playing the second SNES game I ordered on eBay Ys III: Wanderers from Ys in 2009--but I wouldn't be able to play it until late 2012 once I had access to play Super Famicom titles thanks to the Retro Duo that I bought that Summer (which in hindsight is a good system but it lacked an eject button so I had to be careful when I took a game out to play another one because I was afraid of damaging the system or the game each time) before I settled for the Super Famicom on Christmas 2015 (which thankfully has got an eject button, which is already a big plus and makes it vastly superior alone).  Ys IV: Mask of the Sun was the seventh physical Super Famicart I imported from Japan (and the first one I got in full condition, with the box and manual as well), and I found it to be a great experience.  =)

Attacking the invading monsters up North past Minea

I did make a glowing first impression post for it on November 2012 for my StarBlog, but since last year I wanted to expand and update my thoughts on the game in a proper review as I've played many more games since then and a lot could happen in roughly four and a half years.  It was great to utilize Adol's enemy pushing tactic on the Nintendo 16-bit console, making it feel like a return to form for the series; because you're essentially moving and maneuvering yourself the whole way through and attacking without the press of a button you could argue that it (like the first two games) can practically be played on one hand, which is the beauty of this game's combat system, silly though it may be at first glance it is incredibly intuitive.

Defeat the centaur to remove monsters from Esteria

For the first time in the series Adol can be poisoned which you can cure with an antidote or wait it out until its effects wear off, only affecting you when you move but if you hold still you're fine.  It is possible to have up to ten different swords, shields, and armor in this game, which is a high amount considering the five or six sets you got during the preceding titles; however don't get too comfortable with the current equipment that you've equipped because it won't be long 'til you procure the subsequent ones.  The areas are great and fun to explore, the pacing is quick, and it felt to me like a proper sequel to the Ancient Ys Vanished diptych.

One of my grievances with the third Ys (or at least insofar as the Nintendo 16-bit version is concerned) is that it made no effort to tie itself to the earlier two titles let alone reference Adol's adventures, and for that matter there was no mention of Ys or anyone pertaining to it.  That makes the "Wanderers from Ys" subtitle dubious at best, even if it may be referring to Adol and his traveling companion Dogi who are coming from Esteria (except neither of them hail from the titular utopian city).

Dogi does appear in this game and in the end joins Adol on his subsequent quests, but oddly enough he was apparently identified as "Colin" in Ys Book I & II...  I'm not sure if this is true or not, but even if it is it does not change the fact that Ys III feels very disconnected to the previous iterations on account of how self-contained it is.

As someone who really enjoyed Ys Book I & II this fourth installment made me feel right at home in the gameplay department and the fact that you get to revisit the previous places you've been to in the first two games.  Remember that bridge atop the river?  Remember the Roda Tree?

Remember Zeptic Village?  Remember Goban's cabin?

Or even Lance Village and the characters you've met at that point?

And of course who could forget Keith, the human cursed as a goblin who helped you in the second adventure?  It's all here!  =D  All this for me lends Ys IV: Mask of the Sun a great sense of continuity to the earlier two games and made this universe's world so much bigger in the process.  If I had to nitpick here though: why are Tarf's, Maria's, and Keith's hair colors different?

Are you telling me that in-between games they changed their blue or green or red hair color respectively to blonde?  Maybe Tonkin House weren't allowed to use the original characters' color palette, who knows?  Regardless, it's like rekindling with old friends which I like about this A-RPG, and unlike the first two games you can actually walk around inside an NPC's home or store as opposed to being greeted by an anime image of the home's or store's owners.

Ys IV also benefits greatly from having numerous villages with varying NPC character designs as opposed to the one village in Ys III with three identical male and two identical female NPC regulars with no variation given to them whatsoever.  In today's game it wasn't feasibly possible to reach the level cap prior to the final moments of the game, which it was in the third game on account that the enemy's experience point value always remained the same no matter how many times you leveled up to the point where you could reach the level cap before even making it to the halfway point.

Yeah, the enemy's experience point value didn't decrease with each level gained in Lagoon either, but at least you had the sense to move on to the next area as opposed to stopping completely until you reach the level cap like in Ys III, and at least that game's level cap was thirty-five as opposed to sixteen.  While I'm all for a good sidescroller I feel that it's not the right format for Ys, a sentiment Nihon Falcom must've shared when they reinvented it as the top-down viewed Ys: The Oath in Felghana in 2005.

Despite my personal problems with Ys III I do find myself coming back to it once in awhile and do still like it, I just wish that it was much longer than the two or two and a half hours it lasted for.

Lilia, no!!!  =O

There are elements that prevented this game from reaching American shores at the time, among them a handful of open references to some real-life religions which would've probably been taken out altogether if it had been localized due to Nintendo of America's no mention of religion rule (had this game been made after the ESRB rating was formed then maybe they would've been kept).  But even if you took those out of the equation Ys IV: Mask of the Sun is a thematically dark chapter out of the original quadrilogy, with some rather gruesome moments despite the simplistic character sprite work at play.

I remember the first time I played this game how shocked I was seeing what happens to Adol after he's caught by this triad of villains after being blown off to this castle after being caught in a dangerous storm in the raining forest.  Naturally he gets picked off until his HP goes to zero but just when you think it's over they keep on going at it repeatedly to the point of brutalizing him.  He's already knocked out cold, no need to keep on beating the dead horse!  Luckily Leeza came at just the right moment to bring him back to her hometown to nurse him back to normal.

These guys are so screwed... they do realize they're
facing up against the Adol Christin, don't they?

There is one area in the game filled with water that suddenly turns red at one point, the character Leeza is of a complex nature that winds up getting herself mistreated or in trouble during a couple points, answering one of this game's "yes and no" moments wrong will have terrible consequences and result in an automatic game over, and two friendly NPCs actually die in harsh ways (one by being hacked at while another is sacrificed)--they do get revived with a vital item but still that's dark stuff; no way would Nintendo of America have allowed that to pass during its heyday (not even the latter half of Ancient Ys Vanished got this dark).

Now that is not to say this game is all dark for there are moments of adventurous optimism and levity thrown in as well as moments of sanctuary when it comes to visiting most villages, plus revisiting the areas from the first two Ys titles is always a huge pleasure.

Adol going up against six Atorushans

The brisk pace really helps with the combat, especially during boss battles when you can simply just maneuver yourself around or go back and forth until they're down for the count.  Some of the bosses require a bit of strategizing though, an example being to attack as they're beginning to unleash their big attack on you leaving them in a vulnerable spot; if you don't feel that you have what it takes yet I say level grind a bit and then come back and try again.  It's imperative that you save as often as possible so you don't risk losing a life after having gotten a vital item or after having cleared an event or after having leveled up only to have to do it again.  The final boss is different than the one from the previous three games as far as his character and resolution is concerned, though it's odd that the second most powerful equipment is required to survive and defeat him; luckily like the third Ys you can access your menu during battle and pick a healing item or a magic replenishing item in the inventory if you're severely low on health (unlike Ys III however it thankfully has a time clock that you can look at every so often in the status screen to let you know how long you've been playing it).  I also get a kick out of the overlapping dialogue boxes when the same character has more to say like in the previous game which is a unique approach.

Scaling the tower gives you a great chance to
catch a breathtaking view

Ys IV: Mask of the Sun is a very fantastic return to form for the Ys series, reverting back to the gameplay that made the first two games memorable while adding more to the table after the sidescrolling venue didn't go over too well (for this reason alone I liken it to Nintendo's The Legend of Zelda: A Link to the Past in this regard).  =)  While the first three games were released on a roughly annual basis, four years seems like a long time to wait for a new installment, but luckily for Tonkin House and the license holder Nihon Falcom it worked out really great in the long run, and would be (alongside Hudson Soft's Ys IV: The Dawn of Ys) one of the final traditional games in the franchise before facing a big change from the fifth installment onward.  The best thing about this game is that the Nintendo 16-bit console finally saw a proper Ys experience, albeit in Japan only.

Before today's game the closest the Nintendo 16-bit console had to a proper Ys experience was the Tokai Engineering port of Micro Cabin's 1989 breakthrough hit Xak: The Art of Visual Stage nine months prior that February in 1993 (previously filled by Kemco-Seika's maligned 1991 port of Zoom's 1990 Ys clone Lagoon which was localized in America and Europe, having upset them with this knowledge in mind); but whereas Nasir's and Adol Christin's adventures felt complete this felt less like a wholesome adventure and more like one half of one with the other half missing (which is exactly the case, but sadly Xak II: Rising of the Redmoon never got a Super Famicom treatment, nor for that matter any other game in the Xak series)--I want to know where Latok Kart's adventures take him next, dammit!  Too bad it wasn't meant to be.  *sigh*  =(

One could make the argument that SoulBlader falls under the Ys trajectory but to be honest I don't consider it to be an Ys equivalent, despite it being worked on by former Nihon Falcom staff--there are similarities structure-wise, but its versatile gameplay and richly themed story are enough to make the Quintet cult classic its own separate entity.

I did mean what I said months ago when I said what my top three favorite Nihon Falcom titles on the Nintendo 16-bit console were: Koei's underrated port of Brandish being my third choice, Nihon Falcom's direct port of their sidescrolling action-oriented adventure game Popful Mail being my second choice, with the Nihon Falcom-licensed/Tonkin House-developed Ys IV: Mask of the Sun being my number one in this regard.  =)

The best Ys on the system bar none  =)

While the game itself isn't very long the length is rather sufficient as it takes several nonconsecutive hours to beat (somewhere between five to seven depending on how you do), and despite it being written in Japanese it is in my opinion largely easy to follow and very intuitive to play--also, how many A-RPGs do you know of in the Nintendo 16-bit console that actually have horses in them aside from Alcahest and Ruin Arm?  If you're an Ys fan or an Ys enthusiast or just want to play a really good A-RPG you'll have a great time with this game; but if you've only played the first two games and haven't played anything made afterward, I say skip Ys III: Wanderers from Ys and jump right into Ys IV: Mask of the Sun (provided you have the means to play and import it).  It is the true Ys sequel and the definitive Ys chapter on the Super Famicom.  =)

My Personal Score: 9.0/10

<( ^o^)^TO EACH THEIR OWN^(^o^ )>

P.S. I planned to finish this review before the 5th (my birthday) and I did get most of it done by then, but ultimately I took awhile to finalize my review.  Anyway, I turned twenty-six, yay!!!  =)

 

P.S. 2 Last Friday I saw Rupert Sanders' live-action adaptation of Ghost in the Shell in theatres, and neither having read Masamune Shirow's original manga source material nor seen the 1995 anime movie adaptation I was hoping it would be better than the polarized reception made it out to be... unfortunately I ended up agreeing with the consensus.  It was visually arresting to look at and its 3D was effective (really worth the surcharge), but the problem was that I could not get myself invested in the characters (I concur that the main character should've been recast, and normally I like Scarlett Johansson, but it's naught to do with the "whitewashing" controversy; her physical action scenes were solid but her talking bits were hampered by her flat delivery).  But hey, Juliette Binoche managed to last longer here than in Gareth Edwards' 2014 Godzilla, that's a plus.  I honestly liked Sanders' 2012 directorial debut Snow White and the Huntsman (which is a better movie in my opinion and had its share of effective scenes), his follow-up Ghost in the Shell was a step down--so far, my least favorite 2017 movie I saw in theatres.

P.S. 3 Two days later I caught up with Jordan Peele's directorial debut in the form of the horror comedy movie Get Out, and while I was rather ambivalent to watch it despite its unanimous praise I was surprised at how gripping and well-shot and well-done it was during the first two thirds not to mention funny when it called for it; the main characters were likable and shared good chemistry with each other and it was so unconventional given the genre... but then the third act happened which kind of undid the preceding acts for me as it got sadistic and allegorical to the point of uncomfortableness (I don't wish to reveal anything, it's still a good movie, but it's hard to explain why I felt this way without spoiling it or its twists which I'll leave for the people who haven't seen it to find out for themselves)--which, don't get me wrong, I'm sure it was Peele's intent in the context of the story and subject matter, but that was just such a sporadic turn.  Bottom line though: I liked it for the most part, I don't think it's 99% on Rotten Tomatoes good but it is good (I'd say it's 7.5 or 8 out of 10 good).

Thank you for reading my review, please leave me a comment (spam will not be tolerated) and let me know what you think; hope you have a great day, take care!  =D