8. SEWERS & TUNNELS

8.1: Sewers represent large drainage systems found beneath ground level in major cities and create a possible vertical Location below each ground level hex of city boards. This additional dimension allows Infantry to move beneath the surface of the playing board free from the effects of enemy presence or fire at higher levels. Entrance to and exit from this special dimension is limited to Manhole Locations. A unit may never start play already in a sewer. A Manhole Location is any ground level hex marked with a black circle (such as 1AA5 or 21P3) or any paved road hex which intersects with any other road such that at least three hexsides of that hex are crossed by a road, such as 1Y9 (or road hexes containing a sewer symbol such as dG3 and dA3 of Deluxe ASL). Sewers are not usable unless so specified by SSR.

8.2: A unit in a sewer is at level -1 and out of LOS of all units other than any occupying an adjacent or the same (CC only) sewer hex, and/or by any unit directly above it in a Manhole Location which has discovered it via a Sewer Emergence dr. A unit is either in a sewer (Level -1) or Manhole Location (level 0), not both. A unit in a sewer is always concealed by being placed beneath a "Sewer ?" counter, even if not concealed prior to entry of the sewer.

8.3: A unit in a sewer can only be attacked by a unit with a LOS to it. All fire vs a unit in a sewer is PBF and subject to the -2 Hazardous Movement DRM regardless of fire phase. Neither a vehicle nor ordnance/IFE/OBA may fire into a sewer. Q&A

8.4: Only unbroken, non berserk Infantry may enter a sewer system and only at the start of their MPh. Furthermore, only those units granted sewer movement capability by SSR, or who are accompanied by a leader who passes a 4TC at the start of that MPh while in a Manhole hex, may enter the sewer. The latter method of entrance is available only when SSR has specified sewers usable and units of either side not granted the capability wish to attempt entrance. Units in a sewer may not portage more than their IPC nor push a Gun. Sewer movement cannot be used to move beneath any Water Obstacle hex. Q&A

8.41: Sewer movement must start in or beneath a Manhole Location and end beneath a Manhole Location no farther than three hexes away. Sewer movement must be performed as one combined stack whenever more than one unit is in the same sewer Location, and must be declared as Sewer movement and symbolized by placement of a "Sewer?" counter above the moving units. However, prior to actual movement, a dr (Δ) is made to determine who moves the stack; on a dr of 6-7, the units become lost and must move during the MPh to a Sewer Location beneath a Manhole within three hexes of its present position designated by the DEFENDER, and the "Sewer?" counter is flipped to the "Lost?" side. This dr is repeated at the start of the stack's MPh during every friendly MPh that the units remain in the sewer system, but with a +1 drm if the units in question are currently lost. Whenever a lost stack's Final dr ≤ 5, the "Lost?" counter is flipped back to the "Sewer?" side and the ATTACKER moves the stack that turn. Units in a sewer must move during their MPh; they cannot remain motionless, although they can return to a hex occupied during a previous turn. Units in a sewer may use the APh only to advance vertically out of the sewer system and into a Manhole Location (or advance into an adjacent sewer hex for CC; 8.44). Q&A

8.42: Upon ending their MPh, units in a sewer must make a dr on the Sewer Emergence Chart and perform the result for the entire stack.

SEWER EMERGENCE CHART
dr	Action Required
≤ 4	May emerge concealed at owner's option during the APh; not subject to Defensive Fire in the interim.
5‑6	Cannot emerge during this Game Turn; not subject to Defensive Fire in interim.
≥ 7	Discovered. Cannot emerge during this Game Turn; subject only to Defensive Fire from any opposing Infantry in Manhole Location but without benefit of concealment.

The following cumulative drm apply to the Sewer Emergence dr:

-1	Manhole Location is occupied by other friendly unit(s)
-1	Manhole is in a building Location unoccupied by enemy units or is in Road hex not in LOS of Known enemy or all such LOS is Hindered by ≥ +2
+1	Sewer units are currently lost
+1	Per Known enemy Good Order MMC in Manhole Location
+1	Enemy unit(s)* is in adjacent Sewer Location

* A unit (not Dummy) must actually be momentarily revealed to earn this drm.

8.43: A unit in a sewer can attack units in the Manhole Location above it only during the AFPh after having been "discovered" by a Sewer Emergence dr ≥ 7. Such fire is PBF (halved for Area Fire) and subject to the TEM of the Manhole Location.

8.44 APh: Opposing units in the sewer system may not enter an enemy occupied sewer hex during the MPh, and may end their respective MPh's ADJACENT only if they are both beneath adjacent Manhole hexes. Should this situation occur, fire attacks between the adjacent units are allowed at PBF, and the APh can be used by the ATTACKER to move either to the Manhole Location above it (if allowed by the Sewer Emergence dr) or to enter into CC with the adjacent sewer unit(s). See Clarification Q&A

8.45: Any unit which becomes broken or berserk in a sewer is eliminated. An already broken or berserk unit may never enter a sewer Location. Similarly, because units in a Manhole Location are usually unaware of units in a sewer beneath them, they ignore them for purposes of rout or charge.

8.5: No Fortifications are allowed in a sewer. A Manhole Location covered by rubble or Blaze is treated as if no Manhole exists therein, except that moving units in the sewer may still end their MPh beneath it. Should a DC attack in a sewer result in rubble, mark that hex with a rubble counter beneath a sewer counter; no Sewer Movement is allowed into that hex.

8.6 TUNNELS: A tunnel exists only by SSR or DYO, or if a player forfeits a specified Fortified Building Location (23.9) capability in order to have access to a tunnel. [EXC: a Fortified Building Location that is specified by building/hex coordinate cannot be forfeited; see also G1.632 for Japanese pillboxes.] Tunnels are not dug during play; they must be secretly recorded prior to setup. A tunnel consists of two entrance Locations which must be within three hexes of each other. The entrances must be in separate ground level building, pillbox, brush, or woods Locations. The entrance may (if so recorded) lead into an OB given entrenchment. The tunnel may not pass beneath any hex whose base elevation differs from that of its entrance Locations (which must both be at the same elevation) or beneath any Water Obstacle hex. See G11.93 for Cave Complexes. A unit in a tunnel never has LOS to any enemy units and is never subject to any form of attack. Q&A

8.61 MOVEMENT: Only Good-Order/dummy Infantry of the owning side may enter a tunnel during the MPh. A unit may move into a tunnel from one entrance Location at the start of its MPh by being placed beneath a "Sewer?" counter at the opposite entrance hex at the cost of all its MF, and must advance out that entrance concealed during the subsequent APh (even if that hex is occupied by enemy units and is Fortified but would instead be eliminated if the opposite entrance were an enemy-occupied pillbox). A tunnel may never be overstacked, and units in a tunnel may not portage more than their IPC or push a Gun. If the Location left was Encircled, units become pinned and CX upon advancing out. See Clarification

8.62 RtPh: Broken units may enter a tunnel during their RtPh and use it to rout, provided they exit it in the same RtPh. Routing units must begin their rout in the tunnel entrance Location and end it in the opposite Location. Routing units are immune to Interdiction while in a tunnel and may use it to move adjacent to or towards a Known enemy unit, provided that when they emerge they are no closer to any armed enemy unit that was Known when they entered the tunnel, and that they don't become ADJACENT to a Known, unbroken armed enemy unit. Routing units are not concealed when they emerge from a tunnel.

8.63 DESTRUCTION: Any tunnel entrance may be destroyed by any Good Order Infantry unit in the same location without a Known enemy unit at the end of the CCPh provided the entrance/exit has been used in the LOS of that unit and subsequently discovered using the recovery procedures of A4.44. The presence of a tunnel entrance/exit cannot be revealed by Searching.