The document provides an overview of line of sight rules in Advanced Squad Leader (ASL). It defines line of sight as the direct line between the center hexes of a sighting unit and target unit. Terrain along the line of sight may block or hinder line of sight depending on its type and relative heights of units. The document uses examples of applying line of sight rules to determine if targets can be seen over or through various terrain features and obstacles on the board.

1. ASL 101: L EARNING A DVANCED S QUAD L EADER Session 4: Line of Sight with Russ Gifford

3. ASL 101: Line of Sight To shoot at anything in ASL, you have to be able to see the target! This is called a ‘line of sight.’ Line of Sight

4. ASL 101: Line of Sight “ Line of sight” (LOS) means the direct line that connects the center of the hex of the sighting unit to the center of the hex of the target. Any terrain that the line touches must be evaluated as an obstacle - a potential block! Line of Sight

5. ASL 101: Line of Sight Very Important Point! Players may NOT stretch a LOS string EXCEPT to check a DECLARED shot! Meaning, if you check for LOS, you will take the shot even if you do not have LOS! Line of Sight

6. ASL 101: Line of Sight Stretch a sting from the center dot to center dot – if it touches a terrain that blocks, then there is NO LOS. Line of Sight Blocked by the woods!

7. ASL 101: Line of Sight Each type of terrain, and each type of unit in ASL is on this chart! Line of Sight

9. ASL 101: Line of Sight Things this chart tells us: Not an obstacle Hinders LOS, but does NOT block Height of obstacle Line of Sight

10. ASL 101: Line of Sight Check this column Line of Sight

11. ASL 101: Line of Sight Check this column And the terrain in question Line of Sight

12. ASL 101: Line of Sight Check this column And the terrain in question And see the result. Line of Sight

14. ASL 101: Line of Sight What is this? Line of Sight

15. ASL 101: Line of Sight The black box on this chart tells us the terrain is inherent terrain , meaning it takes up the entire hex. If the LOS touches any part of this hex, even just a shared hex spine, it is touching the terrain and the hindrance applies. Line of Sight Rules

16. ASL 101: Line of Sight How many single hex buildings (bldg) can you see? How many are wooden? How many are stone? What level obstacle do they represent? Line of Sight Quiz

17. ASL 101: Line of Sight How many multi-hex buildings (bldg) can you see? What level block do they represent? Line of Sight Quiz

18. ASL 101: Line of Sight See any examples of inherent terrain on this board? Just one – grain Line of Sight Quiz

19. ASL 101: Line of Sight We can see INTO a hex with blocking terrain, but not PAST it. Unless we have a height advantage! Line of Sight

20. ASL 101: Line of Sight We can see INTO a hex X3, but not PAST it to hex Y4. (The building in X3 is a 1 level obstacle. We are at level 0.) Line of Sight

21. ASL 101: Line of Sight We can see INTO the woods in hex X1, but not PAST it to hex Y1. (The woods in X1 is blocking terrain.) Line of Sight

22. ASL 101: Line of Sight We can see INTO the woods in hex W4, but not PAST it. (The woods in X1 is blocking terrain – and so is the hill.) Line of Sight

23. ASL 101: Line of Sight What about the hedge on the W3/X2 hexside? Line of Sight

24. ASL 101: Line of Sight Hexside obstacles are much like in hex terrain: If we touch it, we can see INTO the hex, but not PAST it. Line of Sight

25. ASL 101: Line of Sight So, the hedge blocks LOS from V2 to Y3. Why? Line of Sight

26. ASL 101: Line of Sight So, the hedge blocks LOS from V2 to Y3. Why? Because the attacker and target are on Level 0, and the wall is a ½ level obstacle. Line of Sight

27. ASL 101: Line of Sight What about the LOS from V2 to Y2? Line of Sight Quiz

28. ASL 101: Line of Sight What about the LOS from V2 to Y2? Clear! The LOS does not cross the hedge. Line of Sight Quiz

29. ASL 101: Line of Sight Special note on Hexside obstacles: LOS touches the terrain if it touches a vertex. Line of Sight

30. ASL 101: Line of Sight Other differences with hexside terrain: This LOS crosses the hedge. Is the LOS from W4 to X1 blocked? Line of Sight Quiz

31. ASL 101: Line of Sight Clear! Why? Line of Sight Quiz

32. ASL 101: Line of Sight The MMC is on a hill, at level one. The hedge is only a ½ level block located on a level zero hex – total block height is ½ level. Line of Sight MMC located at Level 1

33. ASL 101: Line of Sight Since the MMC is hirer than the blocking terrain, (Lvl 1 > Lvl ½) the 467 can see over the hedge. Line of Sight MMC located at Level 1

34. ASL 101: Line of Sight Another important point: LOS in ASL is reciprocal – if you can see the target, the target can see you! Line of Sight

35. ASL 101: Line of Sight What about the LOS from W4 to X2? The height of W4 allows them to see over it, but -- the hedge still gives a unit in X2 a +1 TEM. Line of Sight

36. ASL 101: Line of Sight What about the LOS from W4 to Y3? Line of Sight

37. ASL 101: Line of Sight What about the LOS from W4 to Y3? Blocked! Why? Line of Sight

38. ASL 101: Line of Sight The height of W4 is Level 1 – and so is the block height of the building. Can see past it, but need to be HIGHER to see to the ground. Line of Sight

39. ASL 101: Line of Sight What about from W5 to Y2? Line of Sight

40. ASL 101: Line of Sight What about from W5 to Y2? Clear! Why? Line of Sight

41. ASL 101: Line of Sight The height of W5 is Level 2 – and the block height of the building is only level 1. Lvl 2 > Lvl 1 Line of Sight

42. ASL 101: Line of Sight What about W5 to W1? Blocked! Why? Line of Sight

43. ASL 101: Line of Sight While the Woods in W4 is only a Level 1 block – it is ON Level 1, so it has an actual height of Level 2. And that’s the same height as W5. Line of Sight

44. ASL 101: Line of Sight What about W5 to Y3? It looks clear – because terrain is only considered in the LOS if terrain is visible on both sides of the LOS string! Line of Sight

45. ASL 101: Line of Sight If it were touching the building, it would be blocked. Why? Line of Sight

47. ASL 101: Line of Sight Line of Sight Quiz A unit in V4: Can it see T1? T2? V2? V1? What about U1? Those should all be easy.

48. ASL 101: Line of Sight Line of Sight Quiz A unit in V4 is at lvl 1, so draw your lines. T1 and T2 are easy – yes. V1 and V2 are also easy – no. What about U1?

49. ASL 101: Line of Sight Line of Sight Quiz A unit in V4: Can it see U6? Both levels, right? What about R3? Both levels? What about S3?

50. ASL 101: Line of Sight We are only at lvl 1, and the T3 bldg is a lvl 1 obstacle – so we can’t see to the ground. We say S3 has a blind hex at the lower level because of the lvl 1 bldg in T3. But since we are at lvl 1, we can see over the top of a lvl 1 block to see anything at the same level. So we can see the lvl 1 location in S3. Line of Sight

51. ASL 101: Line of Sight Line of Sight On level 1 to level 1 is clear if nothing higher is in between.

52. ASL 101: Line of Sight Line of Sight Quiz A unit in V4: What about LOS to T6?

53. ASL 101: Line of Sight Line of Sight Quiz A unit in V4: Looking at T6, we draw the line. It cuts the corner of U6, so we cannot see EITHER level of T6.

54. ASL 101: Line of Sight Line of Sight Quiz Now, move the unit to U7: Still at lvl 1, and it can see both lvls of T6 and U6. We cannot see T5 or U5 – but can see R5 lvl 1?

55. ASL 101: Line of Sight Line of Sight Quiz From U7: Still at lvl 1, but we cannot see the Lvl 1 locations past T5 and U5 because a multi-hex bldg with no inherent stairwell is a lvl 1 ½ block!

56. ASL 101: Line of Sight Line of Sight Quiz Now - a unit in W5: Can it see U2? R3? Both levels? What about R7? Those should all be easy now.

57. ASL 101: Line of Sight Blind Hexes vary: Obstacles create potential blind hexes behind them equal to their full level height (FRD) Potential, because a height advantage will reduce the number of blind hexes by one for each full level of height advantage beyond the minimum to see past the unit. Line of Sight

58. ASL 101: Line of Sight However: Blind Hexes: Potential Blind hexes increase by one for each multiple of 5 hexes in range (FRD). So – at 1 to 5 hexes, blind hexes as per height. 6 to 10 hexes – blind hexes increase by one hex. 11-15 – blind hexes increased by 2 hexes. Line of Sight

59. ASL 101: Line of Sight OK – so what about hills and blind hexes. Look at W5 to Y4? Is there a 1 hex blind spot behind the level 1 hill? Line of Sight

60. ASL 101: Line of Sight Is there a 1 hex blind spot behind the level 1 hill? No. Hills only create their first blind hex at distances greater than 5 hexes. Line of Sight

61. ASL 101: Line of Sight Line of Sight Quiz Now - a unit in W5: Can it see U6? Both levels? T6? Either level? What about S7?

62. ASL 101: Line of Sight Line of Sight Quiz Now - a unit in W5: U6: Yes. Continuous slope. T6: No. Can’t see through roof! S7: Blind hex!

63. ASL 101: Line of Sight Line of Sight Quiz Last question: Unit in W7: Can it see R5? If yes, which levels?

64. ASL 101: Line of Sight Line of Sight Quiz W7: Lvl 2 T6: Lvl 1 ½ Lvl 2 > Lvl 1 ½ Blind hexes - FRD S6: blind. R5: Clear! (both levels)

65. ASL 101: Line of Sight Line of Sight Quiz Last question: Unit in W7: Can it see R6? If yes, which levels? If no, why not?

66. ASL 101: Line of Sight Line of Sight Quiz W7: Lvl 2 U7: Lvl 1 + Lvl 1 woods = Lvl 2 No height advantage means no LOS

67. ASL 101: Line of Sight Note: Sometimes in ASL, the LOS is drawn to a vertex ( bypass ) or a hexside ( snap shot, road movement ) Line of Sight

68. ASL 101: Line of Sight Does Brush block LOS? Line of Sight

69. ASL 101: Line of Sight Does Brush Block LOS? No – it is a hindrance. Line of Sight