• Raiders raiding from or returning to Bergen or Scapa Flow (21.533D, 21.538B).
  
• Raiders returning after starting the game at sea (21.538B).
  
• Naval units moving to an SW box to engage raiders (21.5342F).
  
• ASW deploying to or from an SW box.
  
• Western Allied transports deploying to or from an SW box (20.622C).
  
• Axis naval units changing base or NRing between Bergen and Oslo or Kiel, while in Norwegian North Sea coastal hexes.
  
• Submarines.
  

• Naval units in the U.S., South Africa and SW boxes.
  
• Naval units in non-operational ports (EXCEPTION: Submarines in fortified ports - 32.248).
  

• A naval force which joins with other naval units in the course of a single naval activity creates a new naval force, which is subject to naval interception even if some or all of its components were intercepted before they combined.
  
• When a naval force sails to a base containing a second naval force in order to combine into a new naval force in that base hex, the naval force which remained in its base until the first naval force arrived may not be intercepted separately. Naval forces may thus be picked up without being subject to interception until they have joined the combined force.
  

EXAMPLE: Japanese TFs sail independently from Manila, Okinawa and Tokyo, rendezvous south of Okinawa and proceed on their mission. The Americans could intercept each of the three groups prior to their rendezvous, and intercept once afterwards. Had the Japanese combined their TFs by sailing the Manila TF to Okinawa, then both TFs to Tokyo, then all three TFs on their mission, the Americans could have intercepted the Manila TF, the combined Manila and Okinawa TFs, and all three TFs, but the Okinawa and Tokyo TFs could not have been intercepted separately.

While sea supply and NRs to different destinations may not support one another (22.141B, C), because their range is unlimited (21.3612), sea transports and seaborne invasions may support one another except in their target hex, as 21.321 prohibits naval forces conducting a sea transport or seaborne invasion from entering the target hex of another sea transport or seaborne invasion.

All good things must come to an end. The moving player may conduct naval activities and counter-intercept; the defender may intercept the moving player’s naval activities and (in rare cases) counter-counter-intercept the moving player’s counter-interceptions. Counter-counter-counter interceptions are prohibited, both because they almost never arise and because the word is too hard to say.

• A naval force may only be spotted by uninverted air units in operational bases within range of the interception hex or any hex along the route to the interception hex. Search AAS and NAS are equivalent for this purpose.
  
• Air units which spot an enemy naval activity are not inverted as a result and are not obliged to attack the enemy naval activity. A given air unit may simultaneously influence any number of interception attempts. An air unit which is already committed to another activity, such as ground support or defensive air support, is not eligible to assist naval interceptions.
  
• Air units attacked by an enemy patrol en route to its patrol hex are considered to have spotted the patrolling force, even if they are eliminated by the patrol.
  
• Anglo-French cooperation restrictions do not prohibit either nation’s air units from assisting in the other’s interceptions; Russo-Allied cooperation restrictions do prohibit such cooperation.
  

• The play of two or more strategic cards than his opponent does not allow a player to roll two or more additional dice. The maximum effect of a strategic codebreaking advantage is one additional die roll for interceptions.
  
• Strategic cards may not reduce the number of dice rolled for naval interceptions.
  

• One fewer die is rolled for two interception attempts; two fewer dice air rolled for three interception attempts; and so on.
  
• This reduction applies to all naval forces attempting to intercept the naval activity in question, but not to naval forces that are attempting to intercept other naval activities.
  
• Submarine interception attempts do not reduce the number of dice rolled for other interception attempts and are not themselves affected by other interception attempts.
  
• Magic interceptions by American TFs (48.61C) are not "interception attempts" and do not reduce the number of dice rolled for interception attempts.

• Europe: If the interception force gets to within 4 hexes of the interception hex: round two; 5-8 hexes: round three; 9-12 hexes: round four; and so on.
  
• Pacific: If the interception force gets to within 2 hexes of the interception hex: round two; 3-4 hexes: round three; 5-6 hexes: round four; and so on.
  
• Interception of an enemy naval force by submarines or attacks on an enemy naval force by air units alone are not sufficient to allow failed interceptions to join in a naval battle.
  

• The decision to withhold naval units from counter-interception naval combat is made on a round-by-round basis. Naval units which are withheld from counter-interception naval combat may be committed to combat in subsequent rounds.
  
• Naval forces which are withheld from counter-interception naval combat remain part of the intercepting naval force, are considered to be screened (22.53), and are vulnerable to and contribute to defense against air and submarine attacks. Intercepting naval units which are screened during all rounds of counter-interception naval combat are not inverted unless they are damaged by enemy attack.
  
• Fast carriers which launch air strikes and fleet units which fire are considered to have engaged in naval combat.
  
• An intercepting naval force which engages in naval combat with an intercepted enemy naval force may not withhold naval units from interception naval combat and is therefore inverted when it returns to base.
  

This rule is required to eliminate a trick on the part of the opponent: if a player attempts to invert a large intercepting naval force which fails to reach its target in its initial attempt by counter-intercepting it with a token force, the intercepting player may choose to use only one or two named ships to eliminate the harassing force, so his remaining forces are eligible to intercept other enemy activities later in that player turn.

• Each player secretly assigns combat group numbers to his participating TFs (22.423). Naval forces which were not part of a TF form a single combat group (22.421).
  

• Each player secretly allocates some, all or none of his carrier-based naval air units to defensive (combat air patrol) operations.
  
• Carrier-based naval air units not assigned to combat air patrol may then counterair enemy land-based air units. A single round of air combat is resolved for each counterair attack (23.61C).
  
• Land-based air units which are not eliminated or forced to abort by a counterair combat result may participate in the ensuing round of naval combat.
  

• Carrier-based air units which are not assigned to combat air patrol, and which were not eliminated or forced to abort by a counterair combat result, including air units which did not counterair, may conduct air strikes against enemy naval units.
  

• Each side announces air cover by land-based air units within range of the naval combat by secretly assigning them to a specific combat group.
  
  • Air units assigned to provide air cover may be used to defend that combat group against attacks by enemy air units.
    
  • Land-based NAS committed to air cover may not be used to search or to attack enemy naval units in that combat round.
    
  • Search and attack AAS may not be used to fly air cover.
    

• whether the combat group consists of less than ten naval factors.
  
• how many fast carriers it contains.
  
• whether it is fast or slow.
  
• whether it is carrying cargo.
  

• One surprise carrier-based air strike per naval combat round.
  
• Non-surprise air strikes.
  

• Each TF unencumbered by cargo forms a separate combat group. Unencumbered TFs may not be broken down and may not combine with other unencumbered TFs to form combat groups.
  
• Intercepting naval forces containing less than ten naval factors unencumbered by cargo combine to form a single combat group.
  
• A naval force carrying cargo, including an unprotected sea supply line and transports carrying cargo, may be strengthened by combining with an unencumbered combat group.
  
• Combat groups formed by combining small naval forces or the combination of encumbered and unencumbered naval forces:
  
  • May not contain more than 25 naval factors; any surplus forms a second, separate combat group, and so on. If a naval force carrying cargo combines with an unencumbered combat group, any surplus must come from the unencumbered combat group. Transports are not counted in determining the size of combat groups.
    
  • Must contain at least one fast fleet factor for each fast carrier factor. Surplus carriers may not voluntarily join in naval combat and must return to port.
    

• If a naval force consisting of more than six combat groups engages in naval combat, surplus combat groups do not take part in the first round of naval combat, but remain on the periphery of the naval battle and are not subject to attack by enemy air or naval units.
  
• Combat groups to which cargo (21.35) has been assigned must participate in naval combat. Otherwise the owning player decides which combat groups engage in naval combat and which are surplus.
  
• After the first round of naval combat is resolved, surplus combat groups may participate in the second round of naval combat only if one or more friendly combat groups withdraw or were eliminated, so that no more than six combat groups participate in the second round of naval combat. Combat groups may not rotate in and out of naval combat. This procedure is repeated until the naval battle is resolved.
  

• Did not reach the interception hex for the first round of naval combat (22.24B); or
  
• Has to wait until another friendly combat group leaves the naval battle before participating (22.421C).
  

• Active combat groups:
  
  • Contribute to search; and
    
  • May initiate fleet combat.
    
• Distant combat groups:
  
  • Contribute to search only if they contain a fully operational fast carrier; and
    
  • Only engage in fleet combat if attacked by an active enemy combat group.
    
• Pending combat groups:
  
  • Take no part in naval combat until they join in a naval battle.
    
  • Are assigned any unused combat group number when they join a naval battle.
    

• One die for each friendly active combat group consisting of at least ten undamaged naval factors (22.428). This modifier applies only to active combat groups; this modifier does not apply to distant combat groups. (Maximum: +6).
  
• One die for each distant combat group containing at least one fully operational fast carrier at the start of the combat round. Active combat groups do not receive an additional modifier for containing fast carriers, and no additional modifier is received by distant combat groups for having more than one fully operational fast carrier in a combat group (Maximum: +5).
  
• Pending combat groups never contribute to search.
  

• whether it consists of less than ten naval factors.
  
• how many fast carriers, if any, it contains.
  
• whether it is fast or slow.
  
• whether it is carrying cargo.
  

• Air Strikes: For each search result against an active or distant enemy combat group, one air strike may be made against that combat group (23.72).
  
• Fleet Combat: For each search result against a distant enemy combat group, one active unpaired combat group may initiate fleet combat against that combat group (22.52). No search results are required for fleet combat between active combat groups and such fleet combat does not count against the limit on the number of air strikes.
  
• Effects Cumulative: The effects of search results are cumulative: two search results would allow any one of the following:
  
  • Two air strikes against any combat group;
    
  • Two fleet combats against a distant combat group; or
    
  • One air strike and one fleet combat against a distant combat group.
    
• Submarine Attacks: Submarine attacks do not count against the limit on the number of times a found combat group may be attacked.
  

• any undamaged carrier in any combat group in their naval force, including carriers in another combat group.
  
• at any air base, subject to stacking limits, within three hexes of the hex in which the naval battle is being fought, but are inverted for the remainder of their player turn if they do so.
  

• any undamaged carrier in any combat group in their naval force, including carriers in another combat group.
  
• If there are not enough undamaged carriers to accommodate the returning naval air units, any surplus naval air units are eliminated.
  

• An opposing active combat group (both fast and slow unpaired active combat groups); or
  
• An opposing distant combat group found by a search roll (fast unpaired active combat groups only).
  

A combat group with a number higher than the current combat round (a “distant” combat group) may only be involved in fleet combat if it is found by the opponent’s search rolls and if the opponent has a fast combat group with a number equal to or lower than the current combat round (an “active” combat group) that did not pair off against an opposing active combat group.
This doesn’t mean higher numbered combat groups are completely safe (if found, they may be subject to an air attack or fleet combat; if found twice, they may be subject to both), but they are safer for longer than they would be if they had a lower combat group number.

• Its combat group number is increased to the next highest available combat group number. The new number must not be in use by another friendly combat group.
  
• The opponent may not again initiate fleet combat against the evading distant combat group in that combat round.
  

EXAMPLE: A naval battle occurs in which Japan and the U.S. each have three combat groups. All are fast except for one American combat group, which is carrying an invasion force.

At the start of the battle, both sides number their combat groups as follows: Japan: CG1, CG2, CG4; U.S.: CG1, CG3, CG5. Japanese CG4 and American CG3 contain fast carriers; American CG5 is carrying cargo.

Neither side has land-based air within range of the naval combat and there is no codebreaking.

Round 1: The search modifiers (22.451) are:

Japan: Zero for the combat round, one for active CG1 and one for the fast carrier(s) in CG4 = 2 dice. Japan rolls 3 and 6.

U.S: Zero for the combat round, one for active CG1 and one for the fast carrier(s) in CG3 = 2 dice. The U.S. rolls 1 and 2.

The search results for Round 1 are:

In Round 1, neither side may launch a surprise air strike (both sides had combat groups found by the opponent - 23.7411B). The Japanese may launch a non-surprise air strike against American CG3 (the only American combat group found by the Japanese); the U.S. may launch non-surprise air strikes against either or both of Japanese CG1 and CG2, as the U.S. found both of these Japanese combat groups.

After these air strikes are resolved, the opposing CG1s engage in fleet combat (22.521A).

Round 2: The search modifiers are:

Japan: One for the combat round, two for active CG1 and CG2 and one for the fast carrier(s) in CG4 = 4 dice. Japan rolls 1, 4, 5 and 5.

U.S: One for the combat round, one for active CG1 and one for the fast carrier(s) in CG3 = 3 dice. The U.S. rolls 2, 4 and 6.

The search results for Round 2 are:

In Round 2, the Japanese may launch a non-surprise air strike against American CG1 or CG5; the U.S. may launch a non-surprise air strike against Japanese CG2 or CG4.

After these air strikes are resolved, the opposing CG1s engage in fleet combat (22.521A).

Japanese CG2, as an unpaired active combat group (22.521D) now has two options. It can engage in fleet combat with American CG1 (an opposing active combat group) or American CG5 (an opposing distant combat group found by a search roll). This second option would be available even if Japan launched an air strike against American CG5 because Japan had two search results for American CG5 (22.452).

If American CG5 were fast, it could evade, and would be renumbered as CG6. However, it is slow, so it has to accept fleet combat.

• Automatic: Damaged ships, fast carriers, destroyers carrying cargo and transports are automatically screened.
  
• Voluntary: A player may elect to screen any other ships in a naval force. The decision to screen is made before naval units are revealed.
  
• Effects: Naval units which are screened from enemy attack:
  
  • may not fire at enemy naval units; and
    
  • may only be fired upon by enemy heavy or light ships which have targeted them if all other friendly, unscreened naval units involved in the fleet combat have first been sunk in that or a previous naval combat round (EXCEPTION: Undamaged cruisers that are damaged by heavy fire are screened and need not be sunk in order to attack screened naval units - 22.54G).
    

• Both sides rank their capital ships as follows:
  
  • larger ships are ranked higher than smaller ships;
    
  • for ships of the same size, faster ships are ranked higher than slower ships;
    
  • for ships of the same size and speed, ships with fewer accumulated hits are ranked higher than ships with more hits;
    
  • for ships of the same size, speed and number of accumulated hits, ships with a higher Naval Nationality DRM are ranked higher than ships with a lower Naval Nationality DRM.
    
• The capital ships then pair off on a one-to-one basis: largest to largest, second largest to second largest, and so on.
  
• If one side has more capital ships than the other, that side is considered to have “surplus capital ships”.
  

• Join with a friendly capital ship in firing at an opposing capital ship; or
  
• Fire on the opposing light ships; or
  
• Hold their fire in the hope of firing on opposing screened ships.
  

• A capital ship which is targeted by one or more opposing capital ships must fire against one of the capital ships firing at it.
  
• All enemy light ships are treated as a single target.
  
• Light ships which are sunk by capital ship fire are removed from the board.
  
• Cruisers which are damaged from capital ship fire are automatically screened and need not be sunk to permit fire on other screened ships (22.54G).
  

• The opposing light ships pair off at a ratio of up to a 3:1 of light ship factors.
  
• If one side has more than three times as many light ship factors as the other, that side is considered to have “surplus light ships”.
  

• Join with friendly light ships in firing at the opposing light ships; or
  
• Fire on one or more opposing capital ships, including those that have already been subject to capital ship fire.
  
  • A single capital ship may be attacked by any number of surplus light ships;
    
  • A second capital ship may only be attacked if the first capital ship is attacked by at least an equal number of surplus light ship factors (so seven surplus light ship factors could attack an opposing four-factor battleship with four, five, six or all seven factors; or up to three surplus light ship factors could instead attack a second opposing four-factor battleship).
    
• Hold their fire in the hope of firing on opposing screened ships.
  

• Fire against screened ships is permitted only if all other enemy capital and light ships, other than cruisers damaged by capital ship fire earlier in the round (22.54C), have been sunk by capital ship and light fire.
  
• Screened named ships are targeted individually; screened light ships are targeted as a group.
  
• Capital ships fire first, then the light ships. Capital and light ships which target the same screened ship or group of screened light ships fire in sequence. Light ships select their targets after capital ship fire is resolved.
  
• Screened ships do not fire back (22.531C).
  

• Submarines may attack (22.9).
  
• Each side may withdraw some, all or none of its naval units from combat (22.6).
  

• If several ships fire together at the same target, the Naval Nationality DRM used is that of the participating nationality with the lowest Naval Nationality DRM.
  
• If a capital ship is the target of enemy fire, its Naval Nationality DRM is used, regardless of what other ships are in its naval force.
  
• If a group of light ships is the target of enemy fire, the group’s Naval Nationality DRM is that of the participating nationality with the lowest Naval Nationality DRM.
  
• CVEs are counted as destroyer factors, with a lower Naval Nationality DRM (22.552A), when determining the strength of forces engaged in fleet combat.
  
• For specific ships:
  
  • Five-factor battleships receive a +1 Naval Nationality DRM;
    
  • the Naval Nationality DRM of carriers is reduced.
    

• If a combat group involved in fleet combat:
  
  • is protecting sea supply; or
    
  • contains destroyers or transports which are conducting sea transport, seaborne invasion or sea escort;
    
  ships in that combat group receive a -1 DRM on their fleet combat dice rolls and the opposing force receives a +1 DRM on fleet combat dice rolls directed against ships in that combat group.
  

• Ships in combat groups which meet more than one of the above criteria still only receive a maximum +/-1 DRM.
  
• This modifier applies even if the mission is intercepted before it has reached the base of embarkation or if it is intercepted while returning to port after it completes its mission.
  
• This modifier applies in the first engagement between raiders and the defending naval units which are stopping the raiders from attacking the defender’s transports, and when raiding naval units attack transports (21.5362C).
  
• The presence of fast carriers or damaged ships does not modify fleet combat dice rolls.
  

EXAMPLE: Three Japanese fleet carriers, with their complement of nine NAS, set sail to bomb an American naval base. They are intercepted and win the ensuing naval combat. The surviving naval air units complete their mission. The carriers, now inverted, are then NRed and subsequently intercepted by other American forces. The Japanese naval air units may participate in the ensuing naval combat (assuming there are any left).

• A victorious force may continue its naval activity or choose to abort that activity and return to its base(s).
  
• A defeated naval force must abort its activity, return to port as per 22.63 and is inverted for the remainder of the player turn (EXCEPTION: Naval units in an SW box - 25.36).
  

• Cargo may not be saved by aborting the activity after the naval losses have been incurred;
  
• Cargo is lost even if the naval losses occurred in a port of embarkation or a destination hex.
  
• Air units may be broken down to accept losses.
  

• If there is a single category of defending ships, that category is attacked.
  
• If there are two categories of defending ships, the target category is determined by rolling one die: 1-3: the higher category (fast carriers or capital ships); 4-6: the lower category (capital ships or light ships).
  
• If there are three categories of defending ships, the target category is determined by rolling one die: 1-2: fast carriers; 3-4: capital ships; 5-6: light ships.
  
• Within each category, the attacker chooses his specific target; light ships are attacked as a group.
  

• Increased by one for every three attacking land-based air squadrons used for search (23.11B) in the submarine attack hex (round down).
  
• Reduced by one for every three defending land-based air squadrons used for search (23.11B) in the submarine attack hex, fully operational fast carriers (regardless of their size) and CVEs in the attacked naval force (round down). Land-based air and carriers are combined, so one searching land-based air squadron, one fully operational fast carrier and one CVE would reduce the submarine attack dice roll by one.
  

• ATLANTIC SW BOX: Excess Western Allied ASW in the Atlantic SW box only modify Axis submarine attacks in western front hexes. Excess Atlantic ASW have no effect on German submarine attacks on Murmansk convoys.
  
• PACIFIC AND INDIAN OCEAN SW BOXES (Western Allies): Excess Western Allied ASW in the Pacific and Indian Ocean SW boxes are combined and modify Japanese submarine attacks anywhere on the Pacific mapboard.
  
• PACIFIC SW BOX (Japan): Excess Japanese ASW in the Pacific SW box modify American submarine attacks anywhere on the Pacific mapboard.