08 February 2021

LEGO® NINJAGO® review: 71720 Fire Stone Mech

Posted by Admin
Kev Levell (on Flickr) takes a deep dive into the 2020 LEGO® NINJAGO® set 71720 Fire Stone Mech today. Buying this set? Consider using our affiliate links: UK LEGO Shop | UK Amazon | USA LEGO Shop | USA Amazon | Australia LEGO Shop, for other countries 'Change Region'. New Elementary may get a commission. The products in this article were provided for free by LEGO; the author's opinions are not biased by this.

An incredible 45 sets were released within the LEGO® NINJAGO® theme in 2020; that’s a lot even allowing for magazine cover mounts and the perennial pocket money “character spinner” variants. It’s a number exceeded only by LEGO Friends sets, while LEGO Star Wars languishes just behind with 43.

The 71720 Fire Stone Mech is one of the larger sets in Ninjago's 2020 ‘Master of the Mountain’ subtheme. He’s a big fella too, weighing in at 667g with a total of 968 pieces including 5 minifigures, all for a comparatively reasonable £64.99 / US$69.99 / 68.23€.

Released in June 2020 in the UK and August in USA/Canada, I have already seen deals at online retailers in the UK with 30% off the RRP. That seems unusual to me for a relatively recently released set, especially one with quite as many new moulds and rare recolours but then again, we live in unusual times… and it would appear that this is an unusual set! Divided in red and grey almost exactly down the middle, like some sort of enormous android Kaiju Harvey Dent in Samurai armour, the Fire Stone Mech is an impressive looking thing.

The parts

There are two new moulds for the second half of 2020 present, yielding just one new exclusive element.

Brick Special 1 x 4 with 3 Layers Curved (part 66955)

This new mould was the main attraction of the set for me. This is an interesting-looking piece and appeared in just three sets in 2020, all from the Master of the Mountain subtheme, and so far in 2021 has made one appearance, in LEGO City 60292 Town Center.

Here, 2 in Dark Stone Grey / Dark Bluish Gray (6301368 | 66955) and 4 in Bright Red/ Red (6301367 | 66955) are provided, and it is the red that is exclusive to this set, Dark Bluish Gray also appears in 71721 Skull Sorcerer’s Dragon and Black is available in 71719 Zane’s Mino Creature and 60292 Town Center.

The sheer complexity of the underside presents mind boggling possibilities for the things we might attach, and how we might attach them. Although this is LEGO, so we might say that about any element you choose to pick up!

BrickLink has taken the slightly bizarre decision (in my opinion) to list this piece as a ‘wedge’, specifically Wedge 4 x 3 No Studs Stepped. I’m not sure where I would have categorised it, but it does follow the curvature of the 1 x 4 curved slope (93273) and all the other parts from that family of bows, as mentioned in TLG's otherwise-terrible name for this part, Design Brick 4X1 w/ Bow.

We’ve been referring to it as the ‘stepped armour’ or ‘stepped panel’ piece, but it isn’t really a panel either. However you choose to categorise it, it is definitely a little bit of an anomaly and therefore deserving of some attention. 

It is overall one brick high by 4 modules wide by 3.5 modules long. A jumper or tile will fit under the lowest protruding ‘step’ or ‘lip’ but a regular plate will not, owing to that curvature.

The layers are not equal, the top step looks to be just under twice the height of the middle step.

Decorative moulded bricks like this are unusual, the ‘layered’ panelling is begging to be used for robot abs or shark’s gills or, if you’re like me, you’ll be inspired to build a sci-fi armadillo/pangolin thing... but I’m getting ahead of myself.

I tried to replicate a similar look with the existing part Vehicle Spoiler 2 x 4 with Handle (98834), but the result is pretty bulky on the construction side.

Slope Curved 2 x 2 with Stud Notches (part 66956)

The next new part is the sequentially numbered Slope Curved 2 x 2 with Stud Notches (66956). In Medium Stone Grey/ Light Bluish Gray (6305049)  it appears in three other sets: 2020's 70433 J.B.'s Submarine and 75280 501st Legion Clone Troopers, and 2021's 75299 Trouble on Tatooine. In Red (6305047) it appears in two other 2020 sets: 71704 Kai Fighter and 80016 The Flaming Foundry. It is in the Fire Stone Mech that they are found in the most plentiful supply in these colours though. Seven of each are included in the Fire Stone Mech but, very unusually, a spare of the Light Bluish Gray is also included which I verified with BrickLink. I haven’t encountered a spare part of this size being included as standard in a System set for a very long time. If I recall correctly, we’re going back to a set from my childhood!

I think it’s a nice part for LEGO to have produced even if it is almost a POOP. When you put 29119 and 29120 together (shown in blue above) the chamfers don’t come to as much of a point as 66956 does and therefore they leave a gap when butted up against one other.

66956 shares a profile with the pentagonal 2x2 piece 27928, but there doesn’t seem to be a satisfying or immediately obvious way to directly connect the two parts.

I gathered together a few of the 45° slopes to see how the part might work in a SNOT situation. I had ideas about space rockets that ultimately didn’t lead to anywhere as interesting as the MOCs Zachary Hill produced for his recent article on this new piece. I guess he took the ‘right angle’ there!

Rare, recoloured or remoulded 

There are a fair number of recolours in this set, and three of those are exclusive. One has already been mentioned; the Brick Special 1 x 4 with 3 Layers Curved in Red (6301367 | 66955).

I have to say I’m surprised that this flag isn’t already available within many, many other sets and in plentiful supply too. However, here it is, the second of our recoloured exclusives: Flag 2 x 2 Trapezoid in Light Bluish Gray (6301896 | 44676) and there are 10 of them included.

Our final exclusive recolour is Windscreen 6 x 6 x 2 Canopy in Transparent Bright Orange/ Trans-Orange (6306825 | 35331), a fairly rare piece in all the colours it appears in (with the exception of trans red perhaps). The question I have is why produce this in Trans-Orange when the part is available already in the very similar Transparent Fluorescent Reddish Orange/ Trans-Neon Orange, as found in  80010 Monkie Kid Bull King? What struck me upon re-reading Tom Loftus' review of that set was the inherent similarities between the structure of these two sets and perhaps that was reason enough to want to further differentiate. Another possible reason is that Trans-Neon Orange is being discontinued by TLG, as suggested by a sticker on the colour palette spotted in a LEGO DOTS designer video a year ago. 

Just 1x Minifig Shield Rectangular with 4 Studs in Light Bluish Gray (6195471 | 30166) is provided. It was new in this colour in 2020 and is available in just six sets. It’s a relatively new piece, originally introduced in printed form in a Star Wars Battle Pack. So far it’s appeared in just four other colours, White, Reddish Brown, Dark Bluish Gray and Dark Red. One of the latter is also included in 71720. I’ve not really explored this part before. and there’s something very appealing about it: it’s functional, the chamfered edges make it aesthetically different, and perhaps therefore lends itself to quite “greebly” uses. 

Large Figure Armor Plate, Small (28220) is a fairly uncommon piece in all of the five colours it has been produced in so far. In Black (6188823), it is only available here and in 2 other sets. It is provided here in light grey too, though sadly just one of each are included.

Slope 45° 2 x 1 with 2/3 Inverted Cutout and no stud in Warm Gold/ Pearl Gold (6287530 | 28192) is featured in 3 other sets. Three other colours of this part appear in the mech: red and light and dark grey.

A set literally full of surprises, as Plate Special 1 x 2 Side Handle [Free Ends] in Pearl Gold (6279731 | 2540) is  another one appearing for the first time this year. Featured only in two sets, an impressive 24 are included here.

Another surprise (for me at least) then; Wedge Sloped 45° 2 x 2 Corner debuts in Red (6301899 | 13548) in the Fire Stone Mech. Why surprising? Well, I grew up with LEGOLAND so I thought all the 45° slopes were made in red, black and blue by default! However this variant was not introduced until 2013 and Red is its 15th colour. 71720 was the only set it appeared in until recently, and BrickLink prices currently reflect this, but I doubt this will be the case for long now that it appears in the super creepy polybag 30565 Birthday Clown.

2 x Tile Special 2 x 3 Pentagonal (22385) has enjoyed inclusion in sets from almost all themes despite it being designed for the now-defunct Nexo Knights range. It appears in Red (6294045) here and in two other sets from 2020, while the excellent 76895 Ferrari Tributo has a decorated version (6291048 | 66866). This is also present in Light Bluish Gray in this set too, with a further three.

Already available in 8 sets this year, just 1 and 1 spare Headwear Accessory Plume / Feather Triple Point in Transparent Bright Green/ Trans-Bright Green (6301652 | 64647) appears in the set. I’ve included it for the sake of thoroughness, but unless green flames set your heart alight, I’m doubtful whether this part will ignite much more inspiration for uses than any of the other 17 colours it comes in have!

Slope 45° 2 x 1 with 2/3 Cutout in Dark Red (6251611 | 15672) is only available in two other sets from 2019 - 9 appear in 10269 Harley-Davidson Fat Boy and you will find 4 in 75958 Beauxbatons' Carriage: Arrival at Hogwarts.

Inspired by the recolours in this set, I created 8 little models especially for our Vibrant Coral supporters on Patreon! Check it out now or via the link at the end of this article.

Printed parts

Aside from the minifigures, there are 4 different decorated elements.

Firstly, a couple of attractively decorated shields both printed on Minifig Shield Round Bowed (75902): one in Pearl Gold with Black/Dark Tan Dragon Drawing print (6302878) and the other in Silver Metallic/ Flat Silver with Black Dragon Drawing print (6302892 | 75902).

Large Figure Shoulder Cover, Armor, Round, Smooth in Red with Gold Decorations print (6302986 | 67984) is used as the top of the mecha’s head and features a detailed ornamental Lion face. We have seen this part repurposed as a head or face a number of times before but (as I’m sure you’re all aware) it was originally introduced as a Constraction figure shoulder pad. An unprinted version in red was previously available in 2017’s 75525 Baze Malbus.

2x Wedge 4 x 4 Fractured Polygon Top in Dark Bluish Gray with Light Bluish Gray Facets Print (6268373 | 52891) appear in this set, which is also available in 70672 Cole’s Dirt Bike. With the same print pattern it furthermore comes in four variants, the first of which appeared over a decade ago!

Minifigures, accessories and weapons

Where minifigures are concerned, cool as they are (particularly Nya in my opinion), new headgear and shoulder pads on Cole, Kai and Nya differentiate our Ninjas from previous waves. The shoulder pad piece appears most interesting or different to me and it comes in two colours:

  • Minifig Neckwear Shoulder Guard in Flat Silver (6301362 | 65435)
  • Minifig Neckwear Shoulder Guard in Pearl Gold (6301364 | 65435)

Moe and Murt, I discovered, are from a tribe of baddies known as Munce, and they are distinguished only by recolours in reddish brown and tan of the studded shoulder pad piece, Minifig Neckwear Shoulder Guard with Tan Teeth/Points (36015). I have to say, I much prefer the black and silver variant that was previously available - much more Rock’n’Roll! 

Sometimes at New Elementary we find phenomenal uses for minifigure accessories, and sometimes these barely scratch the surface of possibilities. For examples of this, see many of our parts festivals. But when a weapon or utensil is more highly specialised (or features fewer connection points for clips, bars or studs) I find myself sorting the part into my minifigure storage, foreseeing very few uses outside its immediate intended purpose. 

Weapon Sword with White Handle, Markings (66954) sadly falls into the latter category. It comes in Black (6300094, shown here on the right) in 71720, and an inverted variant is also available in the Master of the Mountain sets in White (6300095). Nevertheless at some point, I will probably see these little skulls popping out of someone's MOC and think “Oh, clever, why didn’t I think of that?”.

Sticker sheet in 71720 Fire Stone Mech

If you are not a fan of stickers, thankfully there are only 12 here and I feel the designs are reasonably generic so they might not limit further use, if applied. I haven’t used them though as however minor those restrictions might be, my zen/freeform building approach just can’t be held back, man. I’m not sure I feel the model entirely needs the extra decoration anyway.

The model & build

Here he is then. He’s a bulky, bold looking robo-tastic Samurai styled mecha warrior. He’s sporting an eye-catching and contrasting red, grey and gold colour scheme. He’s big, heavy and he made my nine year old son say “That’s COOOOOLLL!”. 

I was surprised by how much fun this was to build, even given the similarities I noticed with sets like 76105 Hulkbuster and 80010 Demon Bull King (not necessarily a bad thing). The structure was understandably very similar if not nearly identical on both sides, but owing to the split colour scheme and a little bit of asymmetry the normal chore of building the mirrored limbs was somewhat alleviated, and in places really enjoyable.

A ton of sideways-building creates some very pleasing shapes. A total of 132 brackets, 18 SNOT bricks and 9 modified plates are included to achieve this. Articulation at the shoulders, elbows and hips allow for some good poseability but the absence of knee joints perhaps limits how dynamic those poses can be without extra support.

Another aspect of the build I liked was the head; some clever use of parts created a really evocative face with a surprising amount of character. The really effective shaping is highly evocative of kabuto and menpo (helmets and masks) from real Samurai armour.

As far as play functions are concerned, there are not many. It seems to be limited to a pair of stud shooters, the dual swords (which are easily removed), a couple of storage areas under the shoulder pads... and a flip-top head!

The lack of knees and play features might just be adult concerns, my children spent a happy half hour playing with the mech and its accompanying minifigures and didn’t express any disappointment.


Aside from being a good build and a fantastic looking robot Samurai warrior (what’s not to like?), you’re getting a lovely bundle of parts. The debatably useful measure of price per piece is 6.7p / 7.2c / 0.07€. Note there are not an excessive number of tiny parts bumping up that total. Furthermore there’s quite a few new parts and a hefty number of rare and recoloured elements, some in good quantities too. So just on paper it’s pretty good value in my opinion, and especially so if you can get it on a reduction. Consider using our affiliate links if you purchase: UK LEGO Shop | UK Amazon | USA LEGO Shop | USA Amazon | Australia LEGO Shop. New Elementary may get a commission.

I’m thinking it’s actually a pretty good parts pack too, the limited colour palette, multiples of elements and a good selection of bits that are good general building pieces as well. I’d like another one of this set just for the parts, so that’s probably a pretty good recommendation. 

Now continue to part 2 where I get inspired by this set's parts to create my own models! Plus, our Vibrant Coral patrons get an exclusive extra treat: 8 further models/tablescraps I created using the recolours in this set.

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  1. I still haven't read most of this review, but I wanted to pause and show my appreciation for using the phrase "enormous android Kaiju Harvey Dent".

  2. Good review! I'm still hoping to maybe pick this set up at some point. Ninjago has been knocking it out of the park with mechs lately.

  3. The new louvered wedge brick reminds me of something I witnessed as a child. My neighbor across the street was a bit of a gearhead, with a couple of trucks that were rated (and used) for off-roading. His wife got the stereotypical Trans-Am (black w/ gold bird on the hood). And she got the stereotypical accessory for that Trans-Am, which was a set of black louvers for the rear window. After he'd installed it, she came outside, looked at it, and declared that it "looked like garbage"...but in a decidedly less polite manner. Looking at this part, I predict it'll end up being used for a Trans-Am MOC pretty much as soon as it comes in black.