The general procedure sketched out for an IJN bombardment of Oahu are drawn from the USMC Landing Operations Doctrine, Chapter V - Naval Gunfire, 1938. It is assumed that if faced with the task, the IJN would have employed similiar tactics
http://www.ibiblio.org/hyperwar/USN/ref ... ous-5.html
The initial purpose of a bombardment of Oahu would be to eliminate the ability of the island's major bases to project air or naval power. The list of potential targets of such an attack would be the United States Navy itself, the large air stations, the naval base, the oil tanks, power generation stations, communications centers and supply dumps. Different guns were better at attacking different targets. Smaller guns were good for precision fire and support work. The large battleship guns were more appropriate for area attacks, as would be the case if striking the navy yard or an airbase,
Battleships.--These must be generally classified as deep support ships, particularly suited for participating in the preparation and for the execution of special missions* beyond the power of the other ships. If, however, hydrographic conditions permit, and there is no danger of the battleship being caught in restricted waters, these ships are ideal for furnishing close supporting fires with their 5-inch batteries
* - Special missions are defined by USMC doctrine as:
Special missions.--The larger caliber guns (8" and above) possess rates of fire too slow and their patterns are too large to make them excellent close support weapons. These large caliber guns are classified tactically as deep support weapons employed on special missions against long range targets as cities, airfields, and major fortifications, and for the destruction of heavy, permanent fortifications. The 8" guns, in the event that 6" guns are not available, can be utilized in long range counterbattery.
The tactical plan to bombard Oahu evolves from the location of the installations to be attacked, the positions of the defending coastal batteries, the depth of the waters around the island, and the maximum range of the Japanese 14", 16" and 18.1" guns firing HE and AA projectiles. The sum of these considerations makes the most efficient direction for an attack roughly southwest of Pearl Harbor, from the deeps waters beyond Barber's Point. The following gives an idea of the range from which a task might be accomplished:
Close support fire: 1,000-10,000 yards.
Indirect spotted fire vs large bases: 20,000-40,000 yards.
Indirect spotted fire vs ships in port: 16,000-24,000 yards.
Indirect spotted fire vs ships in port (elite units): 30,000 yards.
Protecting Oahu against attack relied upon an interlocking system of defenses for success. The fleet, sitting in harbor, provided the vast majority of the anti-aircraft defenses available to the island. These were of a scale such that Kido Butai could not conduct sustained attacks against the navy yard over a period of days without suffering heavy losses.
But the United States fleet could only sit in harbor if no enemy fleet came up to Oahu and destroyed it at pierside. The things that prevented this were the aircraft at Hawaii, the coastal defenses designed to ward off such assaults, and any fire the ships themselves could muster (USN ships were not netted into the coastal defense network, and therefore would have to rely upon their own spotter aircraft). On paper, the coastal defenses looked impressive. But in fact there were only two positions of four guns in total capable of contesting a serious massed attack by battleships and heavy cruisers. These were Battery Hatch and Battery Williston, situated southwest of the harbor, each being open-air 16" guns capable of hurling battleship-killing shells 20 miles out to sea.
If these two coastal batteries were silenced, then IJN fleet could approach closely enough to attack targets in the harbor with indirect fire. If the USN were still in harbor when this happened, then it risked immediate wholesale annihilation. But if the USN instead went to sea to avoid an attack, then Oahu no longer had adequate anti-aircraft defenses to protect itself, and Kido Butai could then do tremendous damage at very little cost.
Tinkerbell proposes that the solution to the problem was combined arms - IJN airpower destroys the 16" coastal guns and sweeps aside any defending ships at sea, operating outside the protective cocoon of massed A.A. in the harbor. IJN heavy surface ships then would approach and clear the port of US ships, which would remove the majority of A.A. defenses and allowing Kido Butai and the surface fleet to destroy Oahu's capability to project air and naval power. To achieve success, significant casualties amongst attacking surface ships was acceptable.
The purpose of a naval bombardment of Oahu would be:
1) To destroy the United States Pacific Fleet in port (the silencing of Williston and Hatch would probably be a prerequisite for such an attack).
2) To conduct saturation bombardments of various targets. (The IJN could perform this mission with the US Army 16" guns operational).
Long range and short range bombardment of Oahu
Method.
Due to the vulnerability of spotter aircraft to defending fighters, the Main Body could not begin an attack without friendly fighters exercising control of the air. Thus a primary prerequisite to a bombardment would be to secure the air superiority necessary to allow the Main Body to approach Oahu. The weather also had to be favorable; a bombardment required good visibility to correct fall of shot. Defending USN vessels at sea would have to be driven away or sunk. Failure to meet these conditions would postpone an attack until whatever difficulty was rectified. Whether targeting ships in the harbor or bases on the island, the organizational element around which an attack is built is the fire group - a number of ships and escorts all tasked to hit targets in a similiar area of the harbor or island,
Firing runs are planned by the fire-support groups within the limits of the respective fire-support areas. The bearing of the firing runs in relation to the line of fire should be such that all the guns of the battery or batteries concerned can bear, and that the range and deflection to the target or targets engaged on the run will change as little as possible during the period of adjustment and fire for effect. The turns at the ends of the run must be made at such times that they do not interfere with the delivery of fires scheduled for specific times nor interrupt the execution of fire on a target of opportunity. >From the standpoint of effective delivery of fire the ideal firing run is on a straight course of maximum length and at minimum speed with the center of the target area bearing on the beam at the center of the run.
Range where commencement of fire would occur would depend upon the target being attacked. For ships in port, not more than 20,000 yards might be optimal. For the the large bases where accuracy wasn't paramount, it would be near the maximum available with the munitions at hand (the large bases were in the order of 50-100 times bigger than a single battleship). IJN training routinely planned for first shots at about the largest ranges possible,
"...by the mid-1930's the Japanese had sufficient confidence in their guns and gunnery that their main force units would outrange those of the US battle fleet by 4,000 to 5,000 meters. With the firepower that the Japanese navy planned to have available, the Naval Staff College estimated that the Japanese could begin to track the enemy at 40,000 meters (21.5 miles) and could...open fire at around 34,000 meters..."
Kaigun, strategy, tactics and technology in the Imperial Japanese Navy, pp262
If making a base attack, each battleship and cruiser would be responsible for attacking an individual installation (ie, Hickam). If attacking ships in port, each fire group would be assigned different areas of the harbor,
"Target areas.--Each fire-support group is assigned a definite land area within which all fires normally to be expected from the group are located."
Certain ships (Nagato, Mutsu, light cruisers, destroyers, plus all secondary batteries without a primary bombardment target) would presumably be responsible for any necessary coastal battery suppression. The method of attack in most cases would be via indirect fire from long range,
Indirect fire.--Indirect fires are fires delivered on targets which cannot be seen from the ship. These fires are spotted by plane spotters or by spotters on shore... The use of indirect fire implies that the target is not visible to the firing ship. However, these fires will usually be observed and adjusted either by air spot or by Shore Fire Control Party spotters
No shore spotters would be available, therefore all gunfire would be directed by aircraft,
Air observers.--Air observers are used primarily to control the deep support batteries of cruisers and battleships in the execution of long range fires. Normally, the ship concerned will supply the plane. The spotter may be a specially trained artillery officer of the landing force. The above arrangement reduces the chances of misunderstandings to a minimum.
IJN battleships and cruisers were capable of performing such a mission because their crews trained extensively to engage enemy ships with indirect fire at ultra-long ranges,
"Another important method of obtaining greater effective gunnery range was through the use of naval aircraft, principally floatplanes carried aboard battleships and cruiser as spotters to mark the fall of shells, thus achieving observational heights not attainable from the mast of any warship...after 1935 the navy could achieve a high rate of hits, using this method, at ranges of over 30,000 meters. The navy practiced this tactical innovation repeatedly in succeeding years, and it was incorporated into Japanese planning for the decisive gunnery duel."
Kaigun, pp260
The technique quoted from Kaigun was practiced exclusively at sea for a decisive naval battle. But the IJN could have adapted to the requirements of a base bombardment fairly easily because the methods employed in their training were identical to those necessary to attack Oahu,
Spotting.--The technique of spotting naval gunfire on shore targets by ship observers is in every respect similar to that employed in spotting fire against waterborne targets, except that the effect of slope must be taken into consideration when making range changes. The technique of spotting by air observers and by Shore Fire Control Party spotters is laid down in the Shore Fire Control Code
Offshore, attacking fire groups would be assigned to bombardment zones according to the location and inclination of their assigned targets. All ships in the same bombardment zone maintain a single line ahead formation, with all fire groups maintaining the same heading and performing turns at the same time. This technique, like all aspects of a bombardment, would require additional pre-war training,
The range to the center of the target is determined by measuring a line joining the ship's position (fixed by continuous navigational plot) and the point designated as the center of the target by the observer (either by coordinates or by reference to a plotted concentration). It is for this reason that a standard map or chart on which has been superimposed the standard grid, and which includes the fire support areas, should be furnished to all firing ships. To the range thus determined is added the position correction necessary because of the altitude of the target. The true bearing of the target is determined and the guns are laid with an appropriate deflection.
Adjustment is accomplished as for direct fire except that full battery salvos are normally used. After each ranging salvo, fire is suspended until the spot is received and applied.
When adjustment is complete and the spotter requests fire for effect, neutralizing fire is delivered as in the engagement of targets by direct fire. If the target has not been sufficiently covered in area or in density, the spotter will transmit an appropriate spot (if necessary), and request that fire for effect be repeated.
Once ranged, each battleship would saturate their target with heavy shells over the course of about 1 to 1.5 hours*.
(* - the Yamato class had a special limitation. She carried 360 rounds in ready store, with another 540 below. It was anticipated that the 360 ready rounds would be replenished from the deeper store rooms between engagements. It was possible to supply the guns from the lower shell rooms during a battle, therefore I allocate Yamato to supply a total of 720 shells in two separate attacks.)
Effect of bombardment.
This site has a pretty good interactive map of Pearl Harbor
http://plasma.nationalgeographic.com/pe ... meset.html
It is assumed that the United States Navy would never have accepted battle while in port. If it did, then the Japanese fleet should have been able to inflict tremendous damage upon it, for it was possible for Japanese ships to come as close as 20,000 yards to the anchorage and still remain outside the range of all but a few of the defending coastal batteries (and of these, none were fortified or camouflaged against air attack).
Barring incredible incompetence, a bombardment of Oahu therefore would probably occur after the USN had moved to sea and been driven from the area by air and/or sea attacks. The effect of a bombardment against land targets is an expression of the total weight of ordnance falling onto each vs. the resistance of the target to the effects of the shells. The size of the targets (airfields, ship yards, oil tank farms) were large enough that in most cases they exceeded the inherent error within the salvo patterns of attacking ships, meaning that most shells fired could be expected to hit the target. How little or how much infrastructure survived such a pounding was dependent on the number, reliability, type and power of the shells fired, and the pure random chance of where each fell within each base's area. Shell classifications were, in order of suppressive effect against exposed troops;
Antiaircraft (air burst).
High capacity (superquick fuze).
Antiaircraft (impact burst).
High capacity (short delay fuze).
Common.
Armor piercing.
To which the IJN would add at some point during 1941 or 1942 another type: The Type III incendiary shell which deposited submunitions projecting a 3000 degree Celsius flame about 15 feet for 5 seconds. Type III incendiaries commenced development in 1938 and entered service in 1942. Presumably, if quantities were issued to the fleet in time, these would not amount to much more than a few dozen shells per ship at most. Still, even in limited quantities their impact on Oahu (post-war USN sniffyness at the concept notwithstanding) would have been quite serious (see below).
Each target on Oahu will be classified by its size and suitability to attack by various types of shells. Type III, HE and AA shells would be better than AP at most jobs not involving concrete surfaces or battleship armor,
The ratio, weight of metal to weight of high explosive, generally fixes the type of fragmentation obtained. When the ratio is small, good fragmentation is obtained and the fragments are effective at greater distances. This is the type of shell used against personnel. When the ratio is large, the fragments produced are few and are effective over an area of smaller radius. This is the type of shell used against material since its heavy walls enable it to defeat the walls of the object hit and introduce the high explosive inside of the object.
The targets for bombardment:
1) Airfields.
"Airfields" are defined in area as the zones of infrastructure, not the airbase including all runways and parks. There are several measurements for effect of shells against airfields. First is their effect on buildings, supplies and equipment. Next, the destruction of the runways and parkways themselves. Finally, the damage/destruction of aircraft caught on the ground. Each shell's effective radius was different depending on which of these objectives it was used for. It was easiest of all to damage parked aircraft, after that buildings and equipment, and finally the runways themselves. As the job got harder, the effective radius of each shell diminished.
2) Oil storage tanks.
Four fields required attack. In Tinkerbell, surface vessels initially attack the oil tanks, with the Strike Force responsible for follow-up strikes against any tanks which escape destruction.
A) Tank Field 1, by Naval Hospital. 156,000 yards sq.
B) Tank Field 2, east of CINPAC HQ. 156,000 yards sq.
C) Tank Field 3, south of CINPAC HQ. 74,000 yards sq.
D) Tank Field 4, on south side of Ford Island. 105,000 yards sq.
3) Navy Yard, Submarine base and Cinpac HQ.
4) Battleships trapped in port or drydock.
5) Schofield Barracks
The IJN must reserve a large portion of heavy shells for a potential naval engagement (or port attack if the USN remained in Pearl Harbor). Tinkerbell calls for most vessels to use only 25% of their heavy caliber ammunition for the bombardment. The exceptions to this rule are Yamamoto's 1st Bombardment Unit (Yamato, Fuso, Yamashiro), which will fire a far larger total of shells, as well as Nagato and Mutsu, which will fire some of their AP at trapped battleships in port.
Shell allocations on various targets
Ship...........Group....Target..............Main Bat...Secondary
Yamato..........1.......Navy Base.........720...............0
Yamato..........1.......Ewa....................0.............1,530 (6.1")
Nagato...........1.......Pennsylvania......150..............0
Nagato...........1.......Counterbat..........80...............0
Nagato...........1.......Navy Base..........50...............0
Mutsu............1.......BB Row..............200.............0
Mutsu............1.......Counterbat...........80..............0
Yamashiro......1.......Hickam AFB.......864.............0
Fuso..............2.......Wheeler..............864.............0
Myoko...........2.......Shofield..............300..............0
Myoko...........2.......Shofield..............300..............0
Hiei...............3.......Ford (N)..............180..............0
Kirishima.......3.......Ford (S)..............180..............0
Kongo...........3.......Cinpac/Sub.........180..............0
Hiei Class(4)..3.......Ewa.....................0..............2,400 (6")
Haruna..........3.......Cinpac/Sub.........180..............0
Mogami x 3....3......Oil Tanks............900..............0
Myoko x 3......4......Navy Base..........900..............0
CL - Counterbattery
DD - Counterbattery
Firepower summary (not including AP or anti-oilfield attack)
Type.....25 lbr eq......HE expended.............Total 25lbr effect
14"...........7.31.................2,448.......................17,895
16"...........9.34...................210........................1,961
18.1".......11.41..................720.........................8,215
8".............3.36.................2,400.......................8,064
6.1"..........1.87.................1,530.......................2,861
6".............1.8...................2,400......................4,320
Total - 43,316 25lbr shell equivalents (equal to 2,566 x 250kg bombs, or 855 Betty bomber attacks)
Base Effect Summary
Base.............Area*......25lbs**....AOA***.......Building****...Cas*****
Hickam...........73..........87...........48%...........80,041..............39
Wheeler..........60.........105..........58%...........80,041..............44
Ewa................39.........184.........102%..........36,674..............64
Ford (South)....33..........40...........22%...........16,675..............20
Ford (North).....24..........55...........30%...........16,675..............26
Cinpac/Sub.....25..........105..........58%...........33,350..............44
Schofield.........49...........41..........23%...........15,372...............21
Navy Base.......82.........143..........79%..........169,688..............55
* - Number of 100 x 100 yard target boxes.
** - # of 25lbr shell equivalents per 100 x 100 yard target box in base area.
*** - Total max. Area of effect of shells as a ratio of base area
**** - Total max. potential building damage area of shells
***** - Number of casualties expected per 1000 men in target area.
Vs. Penn - about 15 expected hits (16")
Vs. Drydock - about 61 hits
Vs. Cassin/Downes - 5hits
Vs Oil tanks - over 90% hit.
Vs. BB Row - about 12-14 hits per ship.
Effects of bombardment against oil tanks.
As previously noted, the berm system at Pearl Harbor was not capable of containing major spills caused by the intensive bombardment of the oil tank system. Aside from forcing the USN to evacuate Hawaii or face fuel starvation, a significant secondary effect of destroying the fields would be the potential to inundate the naval base with burning oil, perhaps destroying it.
F....Tanks......Rad/Rad...Area..........Field
1.......8............30/50.......7854
2......17..........132/152...72,581......2,052,750
3.......9............72/92.....26,590
4......27...........60/80.....20,105.......1,616,900
Tanks - number of tanks in field
Rad/Rad - radius of tank / radius of tank vs. near miss kill. (square feet)
Area - Area of tank (square feet)
Field - Field size, plus 15%.
Bombs required for specified effect in two tank fields:
Field.....................Tanks.............90% hit rate
East of Cinpac........17..................About 65
West of Cinpac.......27..................About 185
Bombs:
About 65 bombs are required to ensure that 90% of the tanks in the field east of Cinpac HQ (2,052,750 square feet) are either hit directly, or near missed within 20 feet. About 185 bombs are needed for the same effect in the field West of Cinpac. Once this level of destruction is achieved, presumably surviving tanks would be targeted individually when identified.
Shells:
Fewer shells will be required to ensure direct hits on tanks because a shell will at the targeted tank farm with a shallower striking angle than a bomb. This increases the target area/field area ratio.
Bombardment of airfields.
Hickam and Wheeler functioned as both as the most important fighter and bomber fields, but as the primary administrative depos for the Hawaiian air command. This is why these are earmarked for very heavy bombardment. Otherwise a primary motive for airfield bombardment is to try to destroy aircraft on the ground. Assuming good visibility, the effectiveness of shellfire against aircraft parked on airfields depends on the density of aircraft on the field, the area over which they are dispersed, and whether or not they are revetted or otherwise fortified from attack, and the type, power, and quantity of shells fired. Airburst A.A. shells and Type III incendiaries vs. aircraft were the most effective against parked in the open. The IJN later employed this technique during the Guadalcanal campaign,
"...They would deluge Henderson Field with 8-inch shells fitted with anti-aircraft time fuses that would burst the projectiles above ground and thus assure a wider scattering of fragments. The Combined Fleet fondly hoped this technique would devastate the Cactus Air Force."
Frank, Guadalcanal, 295
Only one time this method was employed by IJN battleships against an American airfield - the effects achieved were so severe that never again did the USN permit IJN battleships to approach Henderson Field uncontested. Only 104 Type III and 189 HE shells were employed. The apparent reason that the bombardment was so telling was because with AA and incendiary against brittle aircraft, the radius of effect of each shell expanded to it's full A.A. burst zone and/or submunition pattern.
Aircraft Area
The larger the aircraft, the more likely that it would be damaged by a single shell (more plane for the splinters to love). Area is taken as (Length+Span /4)^2 *3.1415
P40 - 107 square yards
SBD - 119 square yards
B-18 - 465 square yards
B-17 - 691 square yards
Lethal shell Area vs. Aircraft.
Type...........Square Yards vs. Aircraft
8".........................234
14".......................697
16".......................924
18"......................1183
Shell effect is measure in units of salvo boxes - the inherent pattern of fall of a salvo. Precisely how big this box should be is a matter of speculation,
http://ibiblio.org/hyperwar/USN/rep/Ley ... -78.3.html
From the performance off SAMAR, it can be concluded that the Japanese have failed to learn one of the axioms of fire control -- that in salvo fire the pattern must be large enough to allow for control error and insure hits once the mean range is established. Their pattern sizes were extremely small. Competent observers have stated and photographic evidence appears to verify the fact that the pattern size was in the neighborhood of 200 to 300 yards. This pattern size proved, after a trial of two and one-half hours, to be entirely too small to insure hits.
78-97
The enemy surface fire seemed to be much inferior to the standard of our navy. This may be due in part to the very small range patterns that the Japanese seem to use. The enemy range pattern, from all types of guns, seldom exceeded 50 yards with ranges up to 9000 yards. In agreement with this supposition is the fact that the number of near misses which did no damage to the ship was unusually high.
Tight patterns at sea were bad because ships could salvo chase, and so greatly reduce the PK of a densely packed group of shells. But vs. land targets, tight patterns were much more dangerous than wider ones because the objects of attention were stationary; their inability to dodge allowing the a smaller and tighter salvos to place a shell directly on the target more quickly, given average luck.
The first chart assumes the salvo pattern to be 40,000 square yards. PK of a miss against an aircraft within 40,000 square yard salvo box is:
((40000 - (Area of Aircraft)/ 40000)^shells fired * ((40000 - (Area of Shell Effect)/40000)^Shells fired
This chart shows the shells expended vs. aircraft type for 25/50/75% probability of kill. The percentage figures tell how many shells must be fired into a 40,000 square yard zone to achieve a 25/50/75% kill rate against the specified aircraft type.
Gun.....Aircraft........25%........50%........75%
8"..........P-40..........34...........82............163
8"..........SBD..........33...........79............157
8"..........B-18..........17...........40............79
8"..........B-17..........13...........30............60
14"........P-40..........14...........35............69
14"........SBD..........14...........34............68
14"........B-18..........10...........24............48
14"........B-17...........9............20............40
16"........P-40..........12...........27............54
16"........SBD..........11...........27............53
16"........B-18...........9............20............40
16"........B-17...........8............17............34
18"........P-40...........9............22............43
18"........SBD...........9............22............43
18"........B-18...........7............17............34
18"........B-17...........7............15............30
Smaller salvo patterns.
The IJN worked very hard to achieve the tightest salvo patterns in the world (200-300 yards off Samar at long range). Assuming that this translated into a box 275 yards long and 75 yards wide (20,625 yards), then
Number of shells required for a 14" AA shell scoring a 75% chance of damaging/destroying an aircraft with 40,000 square yard and 20,625 square yard salvo box:
Type.......40,000..............20,625
P40.............69.....................36
SBD............68.....................35
B-17............40.....................21
The tighter the salvo pattern, the more brutal the effect. For example, a bombardment of 100 x 14" AA shells vs. 18 x B-17 dispersed in a 60,000 square yard area should see around 16 of 18 aircraft destroyed or heavily damaged. Assuming that 24 SBD's were also in the target park with the B-17's, then about 18 of them would also be hit.
Type III Shells.
Gun.......Incendiary submunitions...........Area of scatter pattern.
18.1"...................996........................................50,595
16"......................735........................................39,195
14"......................480........................................19,960
8"........................198..........................................8,639
In the case of the Type III incendiaries, the device pretty much had to land on the aircraft to achieve a kill. For this reason, I'll assume the submunitions as having no lethal radius of destruction, and the aircraft radius at 1/2 it's area for HE effect
PK vs. aircraft for Type III incendiaries is nothing short of brutal.
Shell......Aircraft........Area of Effect..............75% coverage.........Pr. Hit
8".............P-40..............8,639................................6.................73%
8".............B-17..............8,639................................6................100%*
14"...........P-40.............19,960...............................2.................73%
16"...........P-40.............39,195...............................1.................64%
18"...........P-40.............50,595...............................1.................65%
(Vs. B-18, B-17, PBY types, certainty of a hit is about 100% for all shells).
In general, the larger the aircraft the less viable their deployment on Oahu in the face of naval bombardment. Small fighters and single engine bombers, especially near Wheeler, could have been dispersed and fortified against HE attack. (For example, if assuming a 40,000 square yard salvo box it would take 729 x 16" AA shells to destroy 50% of P-40's in an area 1/3 of a square mile when only 459 would be needed if targeting B-17's). Put another way, if Mutsu were hunting individual B-17's by indirect spotted fire, it might take around average of 17-20 big shells to hit each aircraft, assuming only one B-17 per 40,000 square yard salvo box. If Myoko were trying the same trick against a single P-40, it should take 82-100 (which is still a pretty good rate of return for an AA investment, all things considered). Shrinking the salvo box has the direct effect on the number of shells expended - half the box = half the shells for a hit.
With the Type III, the potential devastation is worsened by orders of magnitude. Where Mutsu needed 17+ shells to hit a B-17, now one single shell stands a reasonable chance of dropping a blowtorch right on the aircraft. The same 459 shells needed in the example above could, if Type III, cover almost 6 square miles of ground with a strong chance of a kill. For this reason, any IJN real-life Tinkerbell would have singled out this particular weapon for special production and deployment efforts.
Are you kidding? Most of the Marines captured never made it home. And all the contractors(400 US civilians IIRC) kept on the island by the Japanese were later murdered. 
), other codes the Japnese military were using were being readily broken before Pearl Harbor. This operation would have been TOO BIG and NOISY to hide. 
