diff --git a/icu4j/main/core/src/test/resources/com/ibm/icu/dev/test/rbbi/break_rules/line.txt b/icu4j/main/core/src/test/resources/com/ibm/icu/dev/test/rbbi/break_rules/line.txt
index c68a66b95f20..9f85b7917139 100644
--- a/icu4j/main/core/src/test/resources/com/ibm/icu/dev/test/rbbi/break_rules/line.txt
+++ b/icu4j/main/core/src/test/resources/com/ibm/icu/dev/test/rbbi/break_rules/line.txt
@@ -6,11 +6,7 @@
 # file: line.txt
 #
 # Reference Line Break rules for intltest rbbi/RBBIMonkeyTest.
-# Rules derived from Unicode Standard Annex #14 for Unicode 14.0,
-# with the following modification:
-#
-#         Boundaries between hyphens and following letters are suppressed when
-#         there is a boundary preceding the hyphen. See rule 20.9
+# Rules derived from Unicode Standard Annex #14 for Unicode 16.0.
 #
 #         This corresponds to CSS line-break=strict (BCP47 -u-lb-strict).
 #         It sets characters of class CJ to behave like NS.
@@ -80,6 +76,12 @@ ZWJ = [:LineBreak =  ZWJ:];
 OP30 = [OP - [\p{ea=F}\p{ea=W}\p{ea=H}]];
 CP30 = [CP - [\p{ea=F}\p{ea=W}\p{ea=H}]];
 
+eaFWH            = [\p{ea=F}\p{ea=W}\p{ea=H}];
+eaFWHminusCMOPGL   = [ eaFWH - [CMS OP GL] ];
+eaFWHminusCM     = [ eaFWH - CMS ];
+eaFWHBreakableAtLB19 = [ eaFWH - [NS BA EX CL IN IS GL CMS] ];
+BAminuseaFWH = [BA - eaFWH ];
+
 PiQU = [\p{Pi}&QU];
 PfQU = [\p{Pf}&QU];
 
@@ -116,15 +118,27 @@ LB25:        ((PR | PO)CM*)? ((OP | HY)CM*)? (IS CM*)? NU (CM*(NU | SY | IS))* (
 # Rules LB14 - LB17.
 
 # Moved before LB14, because it matches a supersequence.
+LB20a.3: ( OP CM* SP* | QU CM* | GL CM* ) (PiQU CM* SP*)+ SP (HY | HH) CM* AL;
 LB15a.1:       ( OP CM* SP* | QU CM* | GL CM* ) (PiQU CM* SP*)+ .;
 
+# Moved before LB14.  These are really the cases where LB19a does not apply, but
+# the old LB19 would.  This is to avoid many instances of chaining over two code
+# points.
+LB19a.1: eaFWHminusCMOPGL         ÷ PiQU CM* eaFWHminusCM;
+LB19a.2: eaFWHminusCMOPGL CM* CMS ÷ PiQU CM* eaFWHminusCM;
+LB19a.5: eaFWHminusCM CM* PfQU         ÷ eaFWHBreakableAtLB19;
+LB19a.6: eaFWHminusCM CM* PfQU CM* CMS ÷ eaFWHBreakableAtLB19;
+
 # Moved up, before LB7, because they can match a longer sequence that would also match LB7.
 # For example, the sequence "OP CM SP AL" matches LB14
 # while the prefix of it, "OP CM SP" matches LB7.1
+LB20a.7:     OP CM* SP+ (HY | HH) CM* AL;
 LB14:        OP CM* SP* .;
 
+LB20a.4:       ^ (PiQU CM* SP*)+ SP (HY | HH) CM* AL;
 LB15a.2:       ^ (PiQU CM* SP*)+ .;
 # LB15b/LB15a chaining.
+LB20a.5:       ([^SP] CM* | SP) PfQU CM* (PiQU CM* SP*)+ SP (HY | HH) CM* AL;
 LB15b.1:       ([^SP] CM* | SP) PfQU CM* (PiQU CM* SP*)+ .;
 LB15b.2:       ([^SP] CM* | SP) PfQU CM* ( SP | GL | WJ | CL | QU | CP | EX | IS | SY | BK | CR | LF | NL | ZW | $ );
 
@@ -161,7 +175,9 @@ LB11.1:      [^SP] CM* WJ;
 LB11.2:      SP WJ;
 LB11.3:      WJ CM* [^CM];
 
-LB12:        GL CM* [^CM];
+# Needs to apply before LB12, because the new monkeys are not greedy.
+LB20a.2:   GL (HY | HH) CM* AL;
+LB12:      GL CM* [^CM];
 
 LB12a:       [^SP BA HY] CM* GL;
 
@@ -183,15 +199,16 @@ LB19.1:      QU CM* [^CM];
 LB20.1:      . CM* ZWJ CB;
 LB20.2:      . CM* ÷ CB;
 
+LB20a.6:     CB CM* ZWJ (HY | HH) CM* AL;
 LB20.3:      CB CM* ZWJ [^CM];
 LB20.4:      CB CM* ÷;
 
-# LB 20.09    Don't break between Hyphens and Letters when there is a break preceding the hyphen.
-LB20.09:     ^(HY | HH) CM* AL;
+# LB 20a    Do not break after a word-initial hyphen.
+LB20a.1:     ^(HY | HH) CM* AL;
 
 # Note: Rule 21a must come before 21 to prevent 21.1 from matching HL BA, then
 #       not picking up the continuing match after the BA from 21a.
-LB21a:       HL CM* (HY | BA) CM* [^CM CB];
+LB21a:       HL CM* (HY | BAminuseaFWH) CM* [^CM CB HL];
 
 LB21.1:      . CM* [BA HY NS];
 LB21.2:      BB CM* [^CM CB];
diff --git a/icu4j/main/core/src/test/resources/com/ibm/icu/dev/test/rbbi/break_rules/line_cj.txt b/icu4j/main/core/src/test/resources/com/ibm/icu/dev/test/rbbi/break_rules/line_cj.txt
index bcfc94f05485..7aad76ecf107 100644
--- a/icu4j/main/core/src/test/resources/com/ibm/icu/dev/test/rbbi/break_rules/line_cj.txt
+++ b/icu4j/main/core/src/test/resources/com/ibm/icu/dev/test/rbbi/break_rules/line_cj.txt
@@ -6,7 +6,7 @@
 # file: line.txt
 #
 # Reference Line Break rules for intltest rbbi/RBBIMonkeyTest.
-# Rules derived from Unicode Standard Annex #14 for Unicode 14.0.
+# Rules derived from Unicode Standard Annex #14 for Unicode 16.0.
 #
 # Note: Rule syntax and the monkey test itself are still a work in progress.
 #       They are expected to change with review and the addition of support for rule tailoring.
@@ -80,6 +80,12 @@ CP30 = [CP - [\p{ea=F}\p{ea=W}\p{ea=H}]];
 OP30 = [OP - [\p{ea=F}\p{ea=W}\p{ea=H}]];
 CP30 = [CP - [\p{ea=F}\p{ea=W}\p{ea=H}]];
 
+eaFWH            = [\p{ea=F}\p{ea=W}\p{ea=H}];
+eaFWHminusCMOPGL   = [ eaFWH - [CMS OP GL] ];
+eaFWHminusCM     = [ eaFWH - CMS ];
+eaFWHBreakableAtLB19 = [ eaFWH - [NS BA EX CL IN IS GL CMS] ];
+BAminuseaFWH = [BA - eaFWH ];
+
 PiQU = [\p{Pi}&QU];
 PfQU = [\p{Pf}&QU];
 
@@ -116,15 +122,27 @@ LB25:        ((PR | PO)CM*)? ((OP | HY)CM*)? (IS CM*)? NU (CM*(NU | SY | IS))* (
 # Rules LB14 - LB17.
 
 # Moved before LB14, because it matches a supersequence.
+LB20a.3: ( OP CM* SP* | QU CM* | GL CM* ) (PiQU CM* SP*)+ SP (HY | HH) CM* AL;
 LB15a.1:       ( OP CM* SP* | QU CM* | GL CM* ) (PiQU CM* SP*)+ .;
 
+# Moved before LB14.  These are really the cases where LB19a does not apply, but
+# the old LB19 would.  This is to avoid many instances of chaining over two code
+# points.
+LB19a.1: eaFWHminusCMOPGL         ÷ PiQU CM* eaFWHminusCM;
+LB19a.2: eaFWHminusCMOPGL CM* CMS ÷ PiQU CM* eaFWHminusCM;
+LB19a.5: eaFWHminusCM CM* PfQU         ÷ eaFWHBreakableAtLB19;
+LB19a.6: eaFWHminusCM CM* PfQU CM* CMS ÷ eaFWHBreakableAtLB19;
+
 # Moved up, before LB7, because they can match a longer sequence that would also match LB7.
 # For example, the sequence "OP CM SP AL" matches LB14
 # while the prefix of it, "OP CM SP" matches LB7.1
+LB20a.7:     OP CM* SP+ (HY | HH) CM* AL;
 LB14:        OP CM* SP* .;
 
+LB20a.4:       ^ (PiQU CM* SP*)+ SP (HY | HH) CM* AL;
 LB15a.2:       ^ (PiQU CM* SP*)+ .;
 # LB15b/LB15a chaining.
+LB20a.5:       ([^SP] CM* | SP) PfQU CM* (PiQU CM* SP*)+ SP (HY | HH) CM* AL;
 LB15b.1:       ([^SP] CM* | SP) PfQU CM* (PiQU CM* SP*)+ .;
 LB15b.2:       ([^SP] CM* | SP) PfQU CM* ( SP | GL | WJ | CL | QU | CP | EX | IS | SY | BK | CR | LF | NL | ZW | $ );
 
@@ -161,7 +179,9 @@ LB11.1:      [^SP] CM* WJ;
 LB11.2:      SP WJ;
 LB11.3:      WJ CM* [^CM];
 
-LB12:        GL CM* [^CM];
+# Needs to apply before LB12, because the new monkeys are not greedy.
+LB20a.2:   GL (HY | HH) CM* AL;
+LB12:      GL CM* [^CM];
 
 LB12a:       [^SP BA HY] CM* GL;
 
@@ -183,15 +203,16 @@ LB19.1:      QU CM* [^CM];
 LB20.1:      . CM* ZWJ CB;
 LB20.2:      . CM* ÷ CB;
 
+LB20a.6:     CB CM* ZWJ (HY | HH) CM* AL;
 LB20.3:      CB CM* ZWJ [^CM];
 LB20.4:      CB CM* ÷;
 
-# LB 20.09    Don't break between Hyphens and Letters when there is a break preceding the hyphen.
-LB20.09:     ^(HY | HH) CM* AL;
+# LB 20a    Do not break after a word-initial hyphen.
+LB20a.1:     ^(HY | HH) CM* AL;
 
 # Note: Rule 21a must come before 21 to prevent 21.1 from matching HL BA, then
 #       not picking up the continuing match after the BA from 21a.
-LB21a:       HL CM* (HY | BA) CM* [^CM CB];
+LB21a:       HL CM* (HY | BAminuseaFWH) CM* [^CM CB HL];
 
 LB21.1:      . CM* [BA HY NS];
 LB21.2:      BB CM* [^CM CB];
diff --git a/icu4j/main/core/src/test/resources/com/ibm/icu/dev/test/rbbi/break_rules/line_loose.txt b/icu4j/main/core/src/test/resources/com/ibm/icu/dev/test/rbbi/break_rules/line_loose.txt
index 05c2bea74025..72e7563c9274 100644
--- a/icu4j/main/core/src/test/resources/com/ibm/icu/dev/test/rbbi/break_rules/line_loose.txt
+++ b/icu4j/main/core/src/test/resources/com/ibm/icu/dev/test/rbbi/break_rules/line_loose.txt
@@ -6,7 +6,7 @@
 #  file:  line_loose.txt
 #
 # Reference Line Break rules for intltest rbbi/RBBIMonkeyTest.
-# Rules derived from Unicode Standard Annex #14 for Unicode 14.0.
+# Rules derived from Unicode Standard Annex #14 for Unicode 16.0.
 #
 # Note: Rule syntax and the monkey test itself are still a work in progress.
 #       They are expected to change with review and the addition of support for rule tailoring.
@@ -81,6 +81,12 @@ ZWJ = [:LineBreak =  ZWJ:];
 OP30 = [OP - [\p{ea=F}\p{ea=W}\p{ea=H}]];
 CP30 = [CP - [\p{ea=F}\p{ea=W}\p{ea=H}]];
 
+eaFWH            = [\p{ea=F}\p{ea=W}\p{ea=H}];
+eaFWHminusCMOPGL   = [ eaFWH - [CMS OP GL] ];
+eaFWHminusCM     = [ eaFWH - CMS ];
+eaFWHBreakableAtLB19 = [ eaFWH - [NS BA EX CL IN IS GL CMS] ];
+BAminuseaFWH = [BA - eaFWH ];
+
 PiQU = [\p{Pi}&QU];
 PfQU = [\p{Pf}&QU];
 
@@ -117,15 +123,27 @@ LB25:        ((PR | PO)CM*)? ((OP | HY)CM*)? (IS CM*)? NU (CM*(NU | SY | IS))* (
 # Rules LB14 - LB17.
 
 # Moved before LB14, because it matches a supersequence.
+LB20a.3: ( OP CM* SP* | QU CM* | GL CM* ) (PiQU CM* SP*)+ SP (HY | HH) CM* AL;
 LB15a.1:       ( OP CM* SP* | QU CM* | GL CM* ) (PiQU CM* SP*)+ .;
 
+# Moved before LB14.  These are really the cases where LB19a does not apply, but
+# the old LB19 would.  This is to avoid many instances of chaining over two code
+# points.
+LB19a.1: eaFWHminusCMOPGL         ÷ PiQU CM* eaFWHminusCM;
+LB19a.2: eaFWHminusCMOPGL CM* CMS ÷ PiQU CM* eaFWHminusCM;
+LB19a.5: eaFWHminusCM CM* PfQU         ÷ eaFWHBreakableAtLB19;
+LB19a.6: eaFWHminusCM CM* PfQU CM* CMS ÷ eaFWHBreakableAtLB19;
+
 # Moved up, before LB7, because they can match a longer sequence that would also match LB7.
 # For example, the sequence "OP CM SP AL" matches LB14
 # while the prefix of it, "OP CM SP" matches LB7.1
+LB20a.7:     OP CM* SP+ (HY | HH) CM* AL;
 LB14:        OP CM* SP* .;
 
+LB20a.4:       ^ (PiQU CM* SP*)+ SP (HY | HH) CM* AL;
 LB15a.2:       ^ (PiQU CM* SP*)+ .;
 # LB15b/LB15a chaining.
+LB20a.5:       ([^SP] CM* | SP) PfQU CM* (PiQU CM* SP*)+ SP (HY | HH) CM* AL;
 LB15b.1:       ([^SP] CM* | SP) PfQU CM* (PiQU CM* SP*)+ .;
 LB15b.2:       ([^SP] CM* | SP) PfQU CM* ( SP | GL | WJ | CL | QU | CP | EX | IS | SY | BK | CR | LF | NL | ZW | $ );
 
@@ -162,7 +180,9 @@ LB11.1:      [^SP] CM* WJ;
 LB11.2:      SP WJ;
 LB11.3:      WJ CM* [^CM];
 
-LB12:        GL CM* [^CM];
+# Needs to apply before LB12, because the new monkeys are not greedy.
+LB20a.2:   GL (HY | HH) CM* AL;
+LB12:      GL CM* [^CM];
 
 LB12a:       [^SP BA HY] CM* GL;
 
@@ -184,15 +204,16 @@ LB19.1:      QU CM* [^CM];
 LB20.1:      . CM* ZWJ CB;
 LB20.2:      . CM* ÷ CB;
 
+LB20a.6:     CB CM* ZWJ (HY | HH) CM* AL;
 LB20.3:      CB CM* ZWJ [^CM];
 LB20.4:      CB CM* ÷;
 
-# LB 20.09    Don't break between Hyphens and Letters when there is a break preceding the hyphen.
-LB20.09:     ^(HY | HH) CM* AL;
+# LB 20a    Do not break after a word-initial hyphen.
+LB20a.1:     ^(HY | HH) CM* AL;
 
 # Note: Rule 21a must come before 21 to prevent 21.1 from matching HL BA, then
 #       not picking up the continuing match after the BA from 21a.
-LB21a:       HL CM* (HY | BA) CM* [^CM CB];
+LB21a:       HL CM* (HY | BAminuseaFWH) CM* [^CM CB HL];
 
 LB21.1:      . CM* [BA HY NS];
 LB21.2:      BB CM* [^CM CB];
diff --git a/icu4j/main/core/src/test/resources/com/ibm/icu/dev/test/rbbi/break_rules/line_loose_cj.txt b/icu4j/main/core/src/test/resources/com/ibm/icu/dev/test/rbbi/break_rules/line_loose_cj.txt
index 93a06be94310..99d01874d1fb 100644
--- a/icu4j/main/core/src/test/resources/com/ibm/icu/dev/test/rbbi/break_rules/line_loose_cj.txt
+++ b/icu4j/main/core/src/test/resources/com/ibm/icu/dev/test/rbbi/break_rules/line_loose_cj.txt
@@ -6,7 +6,7 @@
 #  file:  line_loose_cj.txt
 #
 # Reference Line Break rules for intltest rbbi/RBBIMonkeyTest.
-# Rules derived from Unicode Standard Annex #14 for Unicode 14.0.
+# Rules derived from Unicode Standard Annex #14 for Unicode 16.0.
 #
 # Note: Rule syntax and the monkey test itself are still a work in progress.
 #       They are expected to change with review and the addition of support for rule tailoring.
@@ -99,6 +99,12 @@ ZWJ = [:LineBreak =  ZWJ:];
 OP30 = [OP - [\p{ea=F}\p{ea=W}\p{ea=H}]];
 CP30 = [CP - [\p{ea=F}\p{ea=W}\p{ea=H}]];
 
+eaFWH            = [\p{ea=F}\p{ea=W}\p{ea=H}];
+eaFWHminusCMOPGL   = [ eaFWH - [CMS OP GL] ];
+eaFWHminusCM     = [ eaFWH - CMS ];
+eaFWHBreakableAtLB19 = [ eaFWH - [NS BA EX CL IN IS GL CMS] ];
+BAminuseaFWH = [BA - eaFWH ];
+
 PiQU = [\p{Pi}&QU];
 PfQU = [\p{Pf}&QU];
 
@@ -136,15 +142,27 @@ LB25:        ((PR | PO | POX)CM*)? ((OP | HY)CM*)? (IS CM*)? NU (CM*(NU | SY | I
 # Rules LB14 - LB17.
 
 # Moved before LB14, because it matches a supersequence.
+LB20a.3: ( OP CM* SP* | QU CM* | GL CM* ) (PiQU CM* SP*)+ SP (HY | HH) CM* AL;
 LB15a.1:       ( OP CM* SP* | QU CM* | GL CM* ) (PiQU CM* SP*)+ .;
 
+# Moved before LB14.  These are really the cases where LB19a does not apply, but
+# the old LB19 would.  This is to avoid many instances of chaining over two code
+# points.
+LB19a.1: eaFWHminusCMOPGL         ÷ PiQU CM* eaFWHminusCM;
+LB19a.2: eaFWHminusCMOPGL CM* CMS ÷ PiQU CM* eaFWHminusCM;
+LB19a.5: eaFWHminusCM CM* PfQU         ÷ eaFWHBreakableAtLB19;
+LB19a.6: eaFWHminusCM CM* PfQU CM* CMS ÷ eaFWHBreakableAtLB19;
+
 # Moved up, before LB7, because they can match a longer sequence that would also match LB7.
 # For example, the sequence "OP CM SP AL" matches LB14
 # while the prefix of it, "OP CM SP" matches LB7.1
+LB20a.7:     OP CM* SP+ (HY | HH) CM* AL;
 LB14:        OP CM* SP* .;
 
+LB20a.4:       ^ (PiQU CM* SP*)+ SP (HY | HH) CM* AL;
 LB15a.2:       ^ (PiQU CM* SP*)+ .;
 # LB15b/LB15a chaining.
+LB20a.5:       ([^SP] CM* | SP) PfQU CM* (PiQU CM* SP*)+ SP (HY | HH) CM* AL;
 LB15b.1:       ([^SP] CM* | SP) PfQU CM* (PiQU CM* SP*)+ .;
 LB15b.2:       ([^SP] CM* | SP) PfQU CM* ( SP | GL | WJ | CL | QU | CP | EX | IS | SY | BK | CR | LF | NL | ZW | $ );
 
@@ -181,7 +199,9 @@ LB11.1:      [^SP] CM* WJ;
 LB11.2:      SP WJ;
 LB11.3:      WJ CM* [^CM];
 
-LB12:        GL CM* [^CM];
+# Needs to apply before LB12, because the new monkeys are not greedy.
+LB20a.2:   GL (HY | HH) CM* AL;
+LB12:      GL CM* [^CM];
 
 LB12a:       [^SP BA BAX HY] CM* GL;
 
@@ -204,18 +224,19 @@ LB19.1:      QU CM* [^CM];
 LB20.1:      . CM* ZWJ CB;
 LB20.2:      . CM* ÷ CB;
 
+LB20a.6:     CB CM* ZWJ (HY | HH) CM* AL;
 LB20.3:      CB CM* ZWJ [^CM];
 LB20.4:      CB CM* ÷;
 
-# LB 20.09    Don't break between Hyphens and Letters when there is a break preceding the hyphen.
-LB20.09:     ^(HY | HH) CM* AL;
+# LB 20a    Do not break after a word-initial hyphen.
+LB20a.1:     ^(HY | HH) CM* AL;
 
 # Note: Rule 21a must come before 21 to prevent 21.1 from matching HL BA, then
 #       not picking up the continuing match after the BA from 21a.
 # LB 21a Don't break after Hebrew + Hyphen
 #   HL (HY | BA) x
 
-LB21a:       HL CM* (HY | BA | BAX) CM* [^CM CB]?;
+LB21a:       HL CM* (HY | BAminuseaFWH | BAX) CM* [^CM CB HL];
 
 LB21.1:      [^ID] CM* [BA BAX HY NS];
 LB21.2:      ID CM* [BA HY NS];
diff --git a/icu4j/main/core/src/test/resources/com/ibm/icu/dev/test/rbbi/break_rules/line_normal.txt b/icu4j/main/core/src/test/resources/com/ibm/icu/dev/test/rbbi/break_rules/line_normal.txt
index 0397ec5a5f2b..211298539797 100644
--- a/icu4j/main/core/src/test/resources/com/ibm/icu/dev/test/rbbi/break_rules/line_normal.txt
+++ b/icu4j/main/core/src/test/resources/com/ibm/icu/dev/test/rbbi/break_rules/line_normal.txt
@@ -6,7 +6,7 @@
 # file: line_normal.txt
 #
 # Reference Line Break rules for intltest rbbi/RBBIMonkeyTest.
-# Rules derived from Unicode Standard Annex #14 for Unicode 14.0.
+# Rules derived from Unicode Standard Annex #14 for Unicode 16.0.
 #
 # Note: Rule syntax and the monkey test itself are still a work in progress.
 #       They are expected to change with review and the addition of support for rule tailoring.
@@ -82,6 +82,12 @@ ZWJ = [:LineBreak =  ZWJ:];
 OP30 = [OP - [\p{ea=F}\p{ea=W}\p{ea=H}]];
 CP30 = [CP - [\p{ea=F}\p{ea=W}\p{ea=H}]];
 
+eaFWH            = [\p{ea=F}\p{ea=W}\p{ea=H}];
+eaFWHminusCMOPGL   = [ eaFWH - [CMS OP GL] ];
+eaFWHminusCM     = [ eaFWH - CMS ];
+eaFWHBreakableAtLB19 = [ eaFWH - [NS BA EX CL IN IS GL CMS] ];
+BAminuseaFWH = [BA - eaFWH ];
+
 PiQU = [\p{Pi}&QU];
 PfQU = [\p{Pf}&QU];
 
@@ -118,15 +124,27 @@ LB25:        ((PR | PO)CM*)? ((OP | HY)CM*)? (IS CM*)? NU (CM*(NU | SY | IS))* (
 # Rules LB14 - LB17.
 
 # Moved before LB14, because it matches a supersequence.
+LB20a.3: ( OP CM* SP* | QU CM* | GL CM* ) (PiQU CM* SP*)+ SP (HY | HH) CM* AL;
 LB15a.1:       ( OP CM* SP* | QU CM* | GL CM* ) (PiQU CM* SP*)+ .;
 
+# Moved before LB14.  These are really the cases where LB19a does not apply, but
+# the old LB19 would.  This is to avoid many instances of chaining over two code
+# points.
+LB19a.1: eaFWHminusCMOPGL         ÷ PiQU CM* eaFWHminusCM;
+LB19a.2: eaFWHminusCMOPGL CM* CMS ÷ PiQU CM* eaFWHminusCM;
+LB19a.5: eaFWHminusCM CM* PfQU         ÷ eaFWHBreakableAtLB19;
+LB19a.6: eaFWHminusCM CM* PfQU CM* CMS ÷ eaFWHBreakableAtLB19;
+
 # Moved up, before LB7, because they can match a longer sequence that would also match LB7.
 # For example, the sequence "OP CM SP AL" matches LB14
 # while the prefix of it, "OP CM SP" matches LB7.1
+LB20a.7:     OP CM* SP+ (HY | HH) CM* AL;
 LB14:        OP CM* SP* .;
 
+LB20a.4:       ^ (PiQU CM* SP*)+ SP (HY | HH) CM* AL;
 LB15a.2:       ^ (PiQU CM* SP*)+ .;
 # LB15b/LB15a chaining.
+LB20a.5:       ([^SP] CM* | SP) PfQU CM* (PiQU CM* SP*)+ SP (HY | HH) CM* AL;
 LB15b.1:       ([^SP] CM* | SP) PfQU CM* (PiQU CM* SP*)+ .;
 LB15b.2:       ([^SP] CM* | SP) PfQU CM* ( SP | GL | WJ | CL | QU | CP | EX | IS | SY | BK | CR | LF | NL | ZW | $ );
 
@@ -163,7 +181,9 @@ LB11.1:      [^SP] CM* WJ;
 LB11.2:      SP WJ;
 LB11.3:      WJ CM* [^CM];
 
-LB12:        GL CM* [^CM];
+# Needs to apply before LB12, because the new monkeys are not greedy.
+LB20a.2:   GL (HY | HH) CM* AL;
+LB12:      GL CM* [^CM];
 
 LB12a:       [^SP BA HY] CM* GL;
 
@@ -185,15 +205,16 @@ LB19.1:      QU CM* [^CM];
 LB20.1:      . CM* ZWJ CB;
 LB20.2:      . CM* ÷ CB;
 
+LB20a.6:     CB CM* ZWJ (HY | HH) CM* AL;
 LB20.3:      CB CM* ZWJ [^CM];
 LB20.4:      CB CM* ÷;
 
-# LB 20.09    Don't break between Hyphens and Letters when there is a break preceding the hyphen.
-LB20.09:     ^(HY | HH) CM* AL;
+# LB 20a    Do not break after a word-initial hyphen.
+LB20a.1:     ^(HY | HH) CM* AL;
 
 # Note: Rule 21a must come before 21 to prevent 21.1 from matching HL BA, then
 #       not picking up the continuing match after the BA from 21a.
-LB21a:       HL CM* (HY | BA) CM* [^CM CB];
+LB21a:       HL CM* (HY | BAminuseaFWH) CM* [^CM CB HL];
 
 LB21.1:      . CM* [BA HY NS];
 LB21.2:      BB CM* [^CM CB];
diff --git a/icu4j/main/core/src/test/resources/com/ibm/icu/dev/test/rbbi/break_rules/line_normal_cj.txt b/icu4j/main/core/src/test/resources/com/ibm/icu/dev/test/rbbi/break_rules/line_normal_cj.txt
index 04889a31ca4e..2061f9170848 100644
--- a/icu4j/main/core/src/test/resources/com/ibm/icu/dev/test/rbbi/break_rules/line_normal_cj.txt
+++ b/icu4j/main/core/src/test/resources/com/ibm/icu/dev/test/rbbi/break_rules/line_normal_cj.txt
@@ -6,7 +6,7 @@
 #  file:  line_normal_cj.txt
 #
 # Reference Line Break rules for intltest rbbi/RBBIMonkeyTest.
-# Rules derived from Unicode Standard Annex #14 for Unicode 14.0.
+# Rules derived from Unicode Standard Annex #14 for Unicode 16.0.
 #
 # Note: Rule syntax and the monkey test itself are still a work in progress.
 #       They are expected to change with review and the addition of support for rule tailoring.
@@ -84,6 +84,12 @@ ZWJ = [:LineBreak =  ZWJ:];
 OP30 = [OP - [\p{ea=F}\p{ea=W}\p{ea=H}]];
 CP30 = [CP - [\p{ea=F}\p{ea=W}\p{ea=H}]];
 
+eaFWH            = [\p{ea=F}\p{ea=W}\p{ea=H}];
+eaFWHminusCMOPGL   = [ eaFWH - [CMS OP GL] ];
+eaFWHminusCM     = [ eaFWH - CMS ];
+eaFWHBreakableAtLB19 = [ eaFWH - [NS BA EX CL IN IS GL CMS] ];
+BAminuseaFWH = [BA - eaFWH ];
+
 PiQU = [\p{Pi}&QU];
 PfQU = [\p{Pf}&QU];
 
@@ -120,15 +126,27 @@ LB25:        ((PR | PO)CM*)? ((OP | HY)CM*)? (IS CM*)? NU (CM*(NU | SY | IS))* (
 # Rules LB14 - LB17.
 
 # Moved before LB14, because it matches a supersequence.
+LB20a.3: ( OP CM* SP* | QU CM* | GL CM* ) (PiQU CM* SP*)+ SP (HY | HH) CM* AL;
 LB15a.1:       ( OP CM* SP* | QU CM* | GL CM* ) (PiQU CM* SP*)+ .;
 
+# Moved before LB14.  These are really the cases where LB19a does not apply, but
+# the old LB19 would.  This is to avoid many instances of chaining over two code
+# points.
+LB19a.1: eaFWHminusCMOPGL         ÷ PiQU CM* eaFWHminusCM;
+LB19a.2: eaFWHminusCMOPGL CM* CMS ÷ PiQU CM* eaFWHminusCM;
+LB19a.5: eaFWHminusCM CM* PfQU         ÷ eaFWHBreakableAtLB19;
+LB19a.6: eaFWHminusCM CM* PfQU CM* CMS ÷ eaFWHBreakableAtLB19;
+
 # Moved up, before LB7, because they can match a longer sequence that would also match LB7.
 # For example, the sequence "OP CM SP AL" matches LB14
 # while the prefix of it, "OP CM SP" matches LB7.1
+LB20a.7:     OP CM* SP+ (HY | HH) CM* AL;
 LB14:        OP CM* SP* .;
 
+LB20a.4:       ^ (PiQU CM* SP*)+ SP (HY | HH) CM* AL;
 LB15a.2:       ^ (PiQU CM* SP*)+ .;
 # LB15b/LB15a chaining.
+LB20a.5:       ([^SP] CM* | SP) PfQU CM* (PiQU CM* SP*)+ SP (HY | HH) CM* AL;
 LB15b.1:       ([^SP] CM* | SP) PfQU CM* (PiQU CM* SP*)+ .;
 LB15b.2:       ([^SP] CM* | SP) PfQU CM* ( SP | GL | WJ | CL | QU | CP | EX | IS | SY | BK | CR | LF | NL | ZW | $ );
 
@@ -167,7 +185,9 @@ LB11.1:      [^SP] CM* WJ;
 LB11.2:      SP WJ;
 LB11.3:      WJ CM* [^CM];
 
-LB12:        GL CM* [^CM];
+# Needs to apply before LB12, because the new monkeys are not greedy.
+LB20a.2:   GL (HY | HH) CM* AL;
+LB12:      GL CM* [^CM];
 
 LB12a:       [^SP BA HY] CM* GL;
 
@@ -189,15 +209,16 @@ LB19.1:      QU CM* [^CM];
 LB20.1:      . CM* ZWJ CB;
 LB20.2:      . CM* ÷ CB;
 
+LB20a.6:     CB CM* ZWJ (HY | HH) CM* AL;
 LB20.3:      CB CM* ZWJ [^CM];
 LB20.4:      CB CM* ÷;
 
-# LB 20.09    Don't break between Hyphens and Letters when there is a break preceding the hyphen.
-LB20.09:     ^(HY | HH) CM* AL;
+# LB 20a    Do not break after a word-initial hyphen.
+LB20a.1:     ^(HY | HH) CM* AL;
 
 # Note: Rule 21a must come before 21 to prevent 21.1 from matching HL BA, then
 #       not picking up the continuing match after the BA from 21a.
-LB21a:       HL CM* (HY | BA) CM* [^CM CB]?;
+LB21a:       HL CM* (HY | BAminuseaFWH) CM* [^CM CB HL];
 
 # DO allow breaks here before $NSXcm, so don't include it
 LB21.1:      . CM* [BA HY NS];