This is the largest of all the chamber of the mastaba, being 11.6m east-west and 9.2m south-north, so large that the ceiling was supported by six pillars; each of which stands (like those of chamber A10) on a plinth.

It is entered from chamber A11, just east of the centre on its south wall. This entry passageway was designed so that any door would have to open inwards into chamber A11. The passageway is, as usual, decorated on both sides with servants (four in each register) bring offerings into the chamber. Only half of the lower register has survived on the west wall, almost two on the east. No text is included.

The surviving decoration of the walls varies dramatically, with only half the height of the lowest register on the south wall, to almost full height of the actual surface on the north wall.
Opposite the entry, in the north wall, is a large recessed niche containing a standing statue of Mereruka. The wall also contains the entry to his son's addition to the mastaba.
At the northern end of the west wall is the entry to the storerooms, chambers A14-A21.
On the floor, between the two middle pillars, is a large stone tethering ring for animals brought to the statue as offerings ().

The chamber would have been the centre of the funerary cult. The large space would have been lit only by oil lamps and torches, the atmosphere would have been thick with the smell of burning incense. The family and Ka-priests chanting their incantations. It is almost certain that they would have first visited chambers A8 and A11, and placed offerings in front of the false doors, finally to stand before the beautifully coloured edifice of the beloved relative or ancestor.

An entrance was created in this chamber for an extension to the mastaba, for Mereruka's son, Meryteti. This was achieved by cutting through the already decorated north wall, at its eastern end ().

The east section of the wall, to the left of the entry, is really a continuation of the east wall, concluding the decorated scenes.
The large bas-relief, whose upper part is missing, shows Mereruka travelling in a reed boat; his wife squats next to him. Behind him, in the lowest of several registers (), stands one of his sons and his elder brother Ihy. The son holds the titles "Sole Companion, Lector Priest", his name has almost been erased but it is still just readable as Memi. This is the only son to hold these titles elsewhere in the mastaba, but here his identity has been erased. Above these two characters are at least two registers of three servants.
In front of Mereruka, a bird has made its nest in the reeds which are on the bank and among which is also an ibis. A crocodile, with a strange looking mouth, devours one of the fish which fill the water which extends under the whole of this section of wall. Harpoon fishing takes place from the smaller skiff by Mereruka's fishermen. All that remains of the fishermen's scene is their feet, the light craft and the harpoons which are equipped with barbed tips.

The west (larger) section of the wall () is the beginning of the decoration of the chamber and although only half the height of the lowest register now exists, there is enough detail to determine its content.
Next to the entry are represented the mourners; they surround the officiant, the lector-priest, dressed in his panther skin. The text above them says: "Oh Meri, my lord, the honoured one, may Anubis glorify you".
In front of them, many servants carry a way of chest, which is probably very heavy. Notice how this is represented : three porters are shown in the front and three others at the rear, all holding a the carrying pole.
But, behind the chest have been represented five pairs of legs, and the hands clutching the edge. Not wanting to conceal the chest, the artist has represented no porters in front of it. While taking into account these conventions, and the absence of perspective, it can be concluded that this chest was borne by no less than 22 people ! They are preceded by two officials, the at the front holds a sceptre in his right hand. Behind him the official holds only a short rod; whilst in front of him stands another character very much mutilated. Behind the convoy, a woman (probably a wife) and again two more officials. Again the front one carries a sceptre whist the one behind him only carries a short rod.

The next scene () shows the barge and the three rowing boats which will pull it. To the left of the barge some men appear to have fallen in the water (Duell thinks that these are actually pushing the barge to start its journey), but because no text has survived it is impossible to know. It should be noticed that the oarsman stroke differently in each of the three boats.
Next is probably the landing stage (), where funerary equipment has already landed, a short text of description is at the right-hand end: "Necessities for the craftsman and the lector priest". Beyond, the coffin is transported after disembarking from the barge, this time the two officials following the porters.
Finally, outside the tomb (), stands the lector-priest. Facing him (in order, left to right) are mourners, dancers and a kneeling woman offering bread from the table in front of her.

Six fragments are currently placed in the upper area of this section of the south wall, three of which probably belong to the west wall (see left side of and ). Dealing with these fragments left to right, bottom row of four first, they contain the following :
1) epithets and titles of Mereruka and his wife;
2) with the end of a sailing boat on the right, epithets and titles of Mereruka and his wife, with part of the title to an offering scene (- possibly part of the west wall) ;
3) above the end of a sailing barge is a text of a greeting to Mereruka by cemetery officials (- possibly part of the west wall) ;
4) part of a boating scene, with the sails lowered (- possibly part of the west wall) ;
5) (in the upper row) below part of the kheker frieze are titles and the beginning an autobiography of Mereruka;
6) again, below part of the kheker frieze are titles and epithets of Mereruka, with attendants on the right.

On the left, the deceased is accompanied by two of his sons (). The one in front of him (whose image has been chiselled out) was probably that of Memi - Pepyankh, the one behind is unknown because no identifying text is available.

Next, and separated by a vertical line, Mereruka is seated on a chair with his wife squatting in front of him () ; they view the boats shown to the right. Below them, they are accompanied by nine servants. The boating scene may have occupied up the remainder of this wall, as far as the entrance to chamber A14, although only the bottom register and a single boat at the far end of register two have survived. Those of the bottom register all face left, towards Mereruka, and are powered by both sails and oars. This would be normal for boats travelling up-river against the current. The boat of the second register has its sails down and travels in the opposite direction.

Boat #1 ( and ) : The yard-arm is supported by a double mast (as are those of the next two boats), along which walks a monkey (). The rigging supporting the mast and sail is well detailed. Some recent discoveries show the great skill of the Ancients Egyptians in the creation of a wide variety of ropes (see ). Two men operate the two rudders at the stern. In the middle of the ship can be seen a tent and to the rear a chamber in which Mereruka is seated on a chair (now much destroyed). The text above the boat says: "How beautiful is this wind, my friend! This is a good start from Hathor, beloved of the beautiful West!".

Boat #2 ( and ) : Here Mereruka stands near the mast, whilst in the cabin at rear, a man makes Mereruka's bed ready for him to sleep () ; he places the headrest in the upright position. The two lines of text above says: "This ('Gold' has) the beauty of the beautiful thing (created). The beautiful thing, it comes to Hathor, the Mistress the sycamore. In peace, in peace to the mountains of the West.".

Boat #3 ( and ) : On this boat Mereruka is seated in a chair on the deck. The short line of text above the boat says: "A good road towards the beautiful West, in peace".

Boat #4 ( and ) : Mereruka is again seated on the deck. The yard-arm of this boat, and the one following, is only supported by a single mast and only one rudder-man is present. This is obviously a smaller craft. A short column of text is the command to the oarsman: "To starboard, to the beautiful West".

Boat #5 ( and ) : This is the last of the boats sailing upstream. On board the boat, which nears the landing stage, Mereruka is yet again seated on the deck. A sub-register, from the scenes of the register above, intrudes above the stern of the boat. There is no text associated with this boat.

Above the fifth boat ( and ), in the remains of a second register, is a boat with its sails down. This boat travels in a different direction to those of the register below. It travels towards a seated Mereruka at the northern end of the wall. Only a trace of the very bottom of the scene with Mereruka has survived, showing his feet, the claw feet of the chair and the leg of his wife who obviously kneeled in front of him. On the foredeck of the boat a man presents a bird offering to Mereruka. The text above him says: "These are for the ka of Meri, the honoured one of Anubis". The line of text above the boat states: "O man, row for Meri, the honoured one of the gods".

Below the remains of the seated Mereruka and intruding into the boat register below ( and ), a group of three men are approaching the vessel. They are armed with sticks held over their shoulder and they are possibly messengers. They are followed by a servant leading two dogs. This scene and that of Mereruka above, are situated above the entrance to chamber A14, which is the corridor leading to the storerooms.

Originally, this wall could have contained as many as twenty such vessels, in a total of five registers. The full scene could have represented the the pilgrimage to Abydos; it certainly did not represent a funerary voyage, shown by the presence Mereruka on the vessels (very much alive) and also by the fact that the journey takes place in two directions. It should be noted that Mereruka miraculously appears on the deck of all the boats of the flotilla. A trace of him even survives at the stern of the boat in the second register.

With such a high proportion of the wall surviving, much of its original intricacies can be observed. It is effectively divided into seven scenes. To the left of the large statue and its niche are four scenes, and to the right there are two. A doorway to Meryteti's chambers cuts through the set of scenes at far right (east), which had already been completed when this was achieved.

Scene 1 () : Close to the left corner Mereruka is represented seated in a palanquin carried by twelve men. Three servants precede it with their arms crossed; three others follow it, the first holds a mat and a staff, the second carries a chest and the third just holds his long staff. Under the palanquin are two naked dwarfs with a pet monkey and three dogs. Below all of this are thirteen members of the deceased's family, several brothers and sons.

Scene 2 () : Mereruka is represented in the company of two of his sons, all holding hands. The cartouche containing part of the name of the leading son has been erased, but the last part of his name ("ankh") remains; this can only be Pepyankh. He is identified as a lector priest. The son at the rear, also a lector priest, is named Apref. He is also described as "sole companion". Although he is not called a son, his appearance in this important scene with the eldest son Pepyankh, would seem to indicate such a relationship. This is Apref's only appearance.

Scene 3 : This tableau is formed from a set of six superimposed registers () :
- 1st register (). The overall activity is that of fattening hyenas for eating. In the middle, two animals have been placed on their backs with their paws bound, and are being force-fed with cuts of meat and poultry. This would have been a very dangerous activity. On the left, an animal is being brought towards the central area tethered by ropes fastened to its neck. Note that it has a flat stomach. On the right, on the other hand, another animal is led away, fully fed; it doesn't need a restrained anymore, and its stomach clearly rounded.
- 2nd register (). Here there are five gazelles and antelopes. The first (right) has straight horns, those of the second are lyre-shaped; the third has them bent slightly forwards again, those of the fourth are curved almost to its back; finally the fifth, whose body is thinner, has its horns bent at near 90°.
- 3rd register (). Food is being given to three reclining oxen, a fourth drinks from a bowl.
- 4th register (). A man leads four oxen, another man three. At the rear the chief drover leads a single ox without horns.
- 5th register (). Four goats eat whilst lying on the ground.
- 6th register (). This top register shows the manufacture of two boats. The workers dig the first (left) with an adze or cut holes in the planking with a chisel; a man measures the length of the second boat with a rope, and the carpenter having taken the proportions indicates with a plumbline where to place the mast.

Scene 4 () : Mereruka strides forwards, holding the great staff. In front of him stands his wife smelling a lotus flower (). Behind Mereruka stands his mother (), Nedjetempet. This is the first of only three scenes which include Mereruka's mother. Another is at the other side of his statue niche, the third is at the south end of the east wall.
His wife and mother are name in their own column of text, above them. The upper part of the scene is missing, but it would have contained several columns of text listing some of Mereruka's titles and his names.

Scene 5 () : Opposite the entry doorway to the chamber is a large statue of the deceased, approximately 2 metres high. he is clothed in the starched kilt and he wears a thick wig. His arms are held down at his side. The form of his left hand indicates that he originally held something; probably his sceptre. It is strange that he should have been holding it in his left hand.
This statue is at the back of a niche-formed shrine dug into the wall and decorated on the outside with a semi-cylindrical moulding. On the outer uprights are some of his titles. The column of text on the right ends with his full name, Mereruka, the one on the left ends with his other name, Meri.
In front of the shrine is an offering table, made of alabaster, placed on an oblong pedestal preceded by a set of four small steps. On this table, in the shape of the hetep-sign, can again be seen some of his titles. These same titles are repeated on the pedestal.
More titles can be read on the front of the statue base.

Scene 6 () : A symmetrical scene to scene 4, the deceased is with his wife and his mother (). His wife and mother are again named. This copy of the scene (unlike the one at the other side of the statue niche) is complete and contains eleven columns of text above his head (). This lists some of his titles and both of his names.

Scene 7 ( and ) : This last portion of the wall consisted of a number of activities distributed on six registers; the decoration was already finished when a doorway was cut through it to give access to Meryteti's extension of his father's mastaba.

Note that this doorway into C1, like to one into A14 of the west wall, is smaller than most others of the mastaba, being less than 2.0m in height. This does however mean that it did not destroy to much of the original decoration. It only affected the lowest register, which, besides being split horizontally into two sub-registers, is now split down the middle.

The texts within these registers is primarily made up of conversations. Those of the fourth register are, in my opinion, the best.
- 1st register. In the lower of the two sub-registers, on the left (), are three men with their arms crossed on their chest; and on the right (), two men with long staffs. Above, on the left, are four naked children with the long sidelock braids; on the right, are two naked individuals, the first of whom appears to carry a child on his hands.
- 2nd register. In this register, which crosses over the doorway, four women execute an acrobatic move (). Four other artists, two facing two, holding either a mirror or a stick finished with a hand, express different gestures. Finally there are two more dancers.
- 3rd register. An individual, who has his arms bound behind his back, is escorted by six naked men holding a stick finished with either a hand or a feather. To the right, a man crouching on the floor receives kicks from four individuals, either to his leg or his head, while a fifth looks on.
- 4th register. This represents exercises in gymnastics.
- The first group, left, is composed of three men carrying a child on their arms. The text says: "Follow your heart. This is the team that brings you, 'He who is on the neck'."
- The second group is of six men in two teams in a tugging competition. The text, in two parts, says: "Your arms are much stronger than his (therefore) you are not as weak as his opposite!", "My team is stronger than yours; hold on to them (i.e. my hands), friend"
- Next there are three runners, and finally two individuals seated in a bizarre position. The text above the runners says: "Hold on firmly! See, I am coming, friend!".
- 5th register. Here, on the left, can be seen two servants holding various birds. Of the remainder of the register only the bottom part remains and this contained small scenes separated by trees.
- 6th register. With the only the small lower portion on the left remaining, the indication is that this showed more servants bringing more fowl.

This wall is divided into three scenes. The one on right (north) revolves around Mereruka and his wife, facing south. At the other end (south), the activity relates to Mereruka, his wife and his mother. The larger central scene is divided into several registers involving agriculture. The north and south ends of these registers are actually part of the two outer scenes.

At the left-hand (north) side of the wall, the deceased and his wife sit (facing south) side-by-side on a broad seat playing a board game ( and ). A man, at a much smaller scale, squats opposite them. Only the final 'i' of his name survives; this could be Mereruka's son, Meryteti. Below him three servants approach carrying offerings. In a separate sub-register, below the couple, eleven servants stand in various poses, facing south. In front of these more porters bring offerings towards the couple.
Positioned on the left ends of the central registers, more porters bring offerings. Note that the bottom register is continuous with the sub-register beneath the couple and that a pole separates the registers above. Could the board game have taken place under a tent-like structure ?

On the right-hand side of the wall, Mereruka stands facing north ( and ). He is accompanied by his wife and his mother, as found either on side of the statue niche of the north wall. They are viewing the agricultural scenes in front of them. Twelve servants of the Ka stand behind them, the first servant of the second register carries the long pole of probably a sunshade. The leading man of the bottom register has the titles: "Inspector of funerary servants, inspector of scribes".
In front of the family group, displayed at the right-hand end of the registers forming the central scenes, are the forward escort.
In the bottom register a man leads two leashed wolf-hounds, he is also probably part of the forward escort. In the register above, a man carries a long pole, which like the one carried by the man who follows the family group, was again supporting a sunshade. He is preceded by two more men. They, and the pairs of men in the registers immediately above, are more of the forward escort.

Between the two family groups, displayed at either end of the wall, are numerous scenes whose topics are borrowed from life in the fields. Divided into registers, only the bottom three now exist in their entirety. A fourth exists above them, at half of its original height, but enough detail remains to know its content.
Note that these scenes are not separated in any way from the participants involved with the two end scenes of this wall; in fact, they even overlap in some cases.

- 1) a man holds his sandals in his left hand and a supervisor, in front of him, leans on his stick.
- 2) two men pile up of the sheaths of corn; whilst two others tidy the area around the completed heap using pitchforks with three prongs.
- 3) two goatherds make their herd cross a ford. The three lines of text above the scene says: "The goatherd is in the water in the middle of fishes. He converses with the silurid fishes, he exchanges some words with the oxyrhynchus fish. West! Where is the goatherd? A goatherd of the west!"
- 4) a man forces donkeys to cross through the water. The text above the scene says: "Go back to them!"
- 5) two drovers supervise their animals during the passage of a ford (). The one on the left stands in the water, the other on the far bank. The text above this scene says: "Stay close to them (i.e. the other oxen of the herd). I let them return to the middle (i.e. the threshing floor)."
- 6) two men tidy a heap of wheat by striking it with branches, whilst another tidies the area using pitchfork with three prongs (). A finished heap has been decorated and a palm has been place on its top.
- 7) two women sift wheat using sieves () Their texts say: "Winnowing barley" and "Sweeping together barley".

- 1) the main content is that of harvesting the fields. The mature harvest has grown to a good height, and labourers cut the ears with the help of large sickles (several sickles have survived and show that they were made of wood, into which were embedded flints). At this time, the crop was cut high up, leaving the long stems in place. Many centuries later, it was cut at a lower level. Towards the right of the scene, amidst the harvesting of the crop, a flock quails is being caught in a net by four hunters (). Other unwelcome birds can be seen walking amongst the tall corn, pecking the fallen grain (). At the left-hand edge a man plays a long flute setting the pace of the work (). Within the texts, the two harvesters either side of the flute player, comment on the good quality of the barley. Further in front of them, a man shouts "Where are you ?", possibly wanting someone to sharpen his sickle. The man cutting barley behind the bird catchers tells them "Oh men, hurry up". The man in the middle of the last two harvesters informs them: "Beer for me, while you cut barley"; but he is spotted by the overseers, who call out: "Winnowing barley"
- 2) at far left, two harvesters carry small bundles of corn, which they pass to two others (), who in turn pass them to three men packaging them into tight blocks (). When finished they are stored as seen above.

The following scenes feature the transportation of the harvest by donkeys.
- In the first scene, three men stride forcefully towards the action with sticks over their shoulder.
- In the second scene six unladen donkeys arrive driven by a donkey-drover.
- In the third () and sixth scenes, two donkeys carry their burden, held in place by a net.
- In the forth, one is being loaded while the donkey-drover restrains the animal and helps support the load.
- The fifth scene shows three men having to force a stubborn donkey to move (). A man standing to the right holds the discarded load.
- In the seventh, five men carry some sheaves on their head (), a single man awaits their arrival to take the sheaves and to place them on a pile.
All of the text in this register relate the transportation using the donkeys. These stubborn animals do not appear to have changed in the past 4000 years. The commands, possibly shouted, include: "Go you, go!", "Hold on to to him my friend!", "Move!", "What is it with you, you !!!, move!", and even an untranslatable command by a man about to deliver a blow to the donkey.

Only the very bottom of this register has survived. It shows the tillage of the land by means of ploughs dragged by oxen.

Mereruka was originally shown standing on the faces of all six pillars. On the north and south faces he looks towards the aisle between the entry and the statue. On the east and west face he looks north. Of the six pillars only #3 has retained the columns of text; eight on the east and faces, nine on those of the and south. Pillar #1, #4 and #6 have only Mereruka's legs; on pillar #2 Mereruka exists fully, but the text area is missing; with pillar #5 only the base of about 1m height has survived, no imagery.
The text on the faces of pillar #3 contain, as expected, some of the titles of the deceased. There is very little variation in the content of any of the pillar faces, the additional column (the seventh in each case) only extending those on the north and south.

From what survives on the pillars, the images of Mereruka have several differences, (see ) :
Sometimes he wears a shoulder length, braided wig (pillar faces 2s, 2w, and 3w), whilst on others he wears a plain short one (pillar faces 2n, 2e, and 3s).
On five faces (pillar 1w, , 3s, 4n and 6e) he wears a long ankle length skirt, whilst on the others he wears a short knee length kilt.
Again, on five faces (pillar 1e, 2s, , 4w and 6n) he wears the panther skin of a lector-priest over his short kilt, the tail of which hangs down between his legs. The panther skins also has additional details : the fastening over his shoulder and the emblem on his chest. These are beautifully illustrated on the of Duell's publication.
He always holds his long staff of office in front of him. But sometimes, in his other hand, he holds a sceptre (pillar faces 2s, 2w, , 3w, 4w, 6n), whilst on other occasions he holds a folded piece of cloth (pillar faces 2n, 2e, ). Only once, in those images which still exist, does he have an empty hand, this is on the south face of pillar 3 ().

Only once is Mereruka accompanied by his son, Meryteti, on pillar 2, the .

This whole north-west area is given over to storerooms. Chambers A14 and A16 are in fact the interconnecting corridors.
A14 is entered from the north-west corner of A13, through an entrance which is smaller than most in the structure. It is only 1.6m in height, though its width is normal at 0.7m. It is designed for a door opening into the corridor. A14 is about 4.4m long and just over 1.0m wide.
At the west end of A14 the direct changes south, into corridor A16, which has a width of 1.4m and a length of 6.6m.
Storeroom A15 is entered from halfway along the south wall of A14. It has a width of 2.1m (east-west) and a length of 1.9m. The south wall of the chamber has been cut through and communication established between this and chamber A9 (through its north wall).
All of the other storerooms are accessed from corridor A16. Rooms A17-A19 having the same dimensions : 2.3m east-west and 1.5m north-south. Rooms A20 and A21 merge with each other and are accessed from the southern end of corridor A16. The size of A21 is similar to rooms A17-A19, but A20 is slightly smaller and of an irregular shape. These two chambers may in fact have been considered as one.
In antiquity, a doorway appears to have been cut through between the east wall of A20 and the west wall of A9, after the completion of the decoration in A9. This was again blocked up in antiquity.

None of these chambers (corridors and storerooms) had been decorated, although above the doorways into chambers A15 and A17-A20 is a small inscription which states that they are all "second class" storerooms and indicates their possible use. The fact that A21 does not carry an inscription further indicates that the two rooms (A20-A21) were in fact only one; the numbering being the invention of the modern day archaeologists. All of the storerooms, with the exception of A21, were designed for inward opening doors.